[INFO] cloning repository https://github.com/hankgong/leetcoderusted
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/hankgong/leetcoderusted" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fhankgong%2Fleetcoderusted", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fhankgong%2Fleetcoderusted'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 22496ba7d6d67fa854b0447a14979c2f704f3e7f
[INFO] testing hankgong/leetcoderusted against 1.49.0 for beta-1.50-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fhankgong%2Fleetcoderusted" "/workspace/builds/worker-3/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-3/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/hankgong/leetcoderusted on toolchain 1.49.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/hankgong/leetcoderusted
[INFO] finished tweaking git repo https://github.com/hankgong/leetcoderusted
[INFO] tweaked toml for git repo https://github.com/hankgong/leetcoderusted written to /workspace/builds/worker-3/source/Cargo.toml
[INFO] crate git repo https://github.com/hankgong/leetcoderusted already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 9e3b6ac953571757cd363e0a554ad7d9dadc5bf0744a66288a14786865f6edaf
[INFO] running `Command { std: "docker" "start" "-a" "9e3b6ac953571757cd363e0a554ad7d9dadc5bf0744a66288a14786865f6edaf", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "9e3b6ac953571757cd363e0a554ad7d9dadc5bf0744a66288a14786865f6edaf", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9e3b6ac953571757cd363e0a554ad7d9dadc5bf0744a66288a14786865f6edaf", kill_on_drop: false }`
[INFO] [stdout] 9e3b6ac953571757cd363e0a554ad7d9dadc5bf0744a66288a14786865f6edaf
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 47ca4cbee5551d6b59ab1b96035f881e6fc0635d1ae48502e074cf9defff87a3
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "47ca4cbee5551d6b59ab1b96035f881e6fc0635d1ae48502e074cf9defff87a3", kill_on_drop: false }`
[INFO] [stderr]    Compiling leetcoderusted v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.55s
[INFO] running `Command { std: "docker" "inspect" "47ca4cbee5551d6b59ab1b96035f881e6fc0635d1ae48502e074cf9defff87a3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "47ca4cbee5551d6b59ab1b96035f881e6fc0635d1ae48502e074cf9defff87a3", kill_on_drop: false }`
[INFO] [stdout] 47ca4cbee5551d6b59ab1b96035f881e6fc0635d1ae48502e074cf9defff87a3
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 56e9ee4eaa9f9a0c94421ef380aa2a004475f59fbb97a6b4d357e59107f27881
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "56e9ee4eaa9f9a0c94421ef380aa2a004475f59fbb97a6b4d357e59107f27881", kill_on_drop: false }`
[INFO] [stderr]    Compiling leetcoderusted v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unnecessary parentheses around `for` iterator expression
[INFO] [stdout]   --> tests/1502e_can_make_arithmetic_prog_from_seq.rs:36:18
[INFO] [stdout]    |
[INFO] [stdout] 36 |         for i in (1..sorted.len()) {
[INFO] [stdout]    |                  ^^^^^^^^^^^^^^^^^ help: remove these parentheses
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_parens)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `idx`
[INFO] [stdout]   --> tests/1512e_number_of_good_pairs.rs:39:13
[INFO] [stdout]    |
[INFO] [stdout] 39 |         let mut idx = 1;
[INFO] [stdout]    |             ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_idx`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `k`
[INFO] [stdout]   --> tests/1512e_number_of_good_pairs.rs:47:14
[INFO] [stdout]    |
[INFO] [stdout] 47 |         for (k, v) in cmap {
[INFO] [stdout]    |              ^ help: if this is intentional, prefix it with an underscore: `_k`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> tests/1512e_number_of_good_pairs.rs:39:13
[INFO] [stdout]    |
[INFO] [stdout] 39 |         let mut idx = 1;
[INFO] [stdout]    |             ----^^^
[INFO] [stdout]    |             |
[INFO] [stdout]    |             help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::collections::HashMap`
[INFO] [stdout]   --> tests/1337e_k_weakest_rows_in_a_matrix.rs:55:5
[INFO] [stdout]    |
[INFO] [stdout] 55 | use std::collections::HashMap;
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 9.18s
[INFO] running `Command { std: "docker" "inspect" "56e9ee4eaa9f9a0c94421ef380aa2a004475f59fbb97a6b4d357e59107f27881", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "56e9ee4eaa9f9a0c94421ef380aa2a004475f59fbb97a6b4d357e59107f27881", kill_on_drop: false }`
[INFO] [stdout] 56e9ee4eaa9f9a0c94421ef380aa2a004475f59fbb97a6b4d357e59107f27881
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] 9f6f35749abbc5f5eb052bec5f8215329b1d935ff5722d75bc9e106ce3d90ffd
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "9f6f35749abbc5f5eb052bec5f8215329b1d935ff5722d75bc9e106ce3d90ffd", kill_on_drop: false }`
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stderr] warning: unnecessary parentheses around `for` iterator expression
[INFO] [stderr]   --> tests/1502e_can_make_arithmetic_prog_from_seq.rs:36:18
[INFO] [stderr]    |
[INFO] [stderr] 36 |         for i in (1..sorted.len()) {
[INFO] [stderr]    |                  ^^^^^^^^^^^^^^^^^ help: remove these parentheses
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_parens)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: 1 warning emitted
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `idx`
[INFO] [stderr]   --> tests/1512e_number_of_good_pairs.rs:39:13
[INFO] [stderr]    |
[INFO] [stderr] 39 |         let mut idx = 1;
[INFO] [stderr]    |             ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_idx`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `k`
[INFO] [stderr]   --> tests/1512e_number_of_good_pairs.rs:47:14
[INFO] [stderr]    |
[INFO] [stderr] 47 |         for (k, v) in cmap {
[INFO] [stderr]    |              ^ help: if this is intentional, prefix it with an underscore: `_k`
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> tests/1512e_number_of_good_pairs.rs:39:13
[INFO] [stderr]    |
[INFO] [stderr] 39 |         let mut idx = 1;
[INFO] [stderr]    |             ----^^^
[INFO] [stderr]    |             |
[INFO] [stderr]    |             help: remove this `mut`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: 3 warnings emitted
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `std::collections::HashMap`
[INFO] [stderr]   --> tests/1337e_k_weakest_rows_in_a_matrix.rs:55:5
[INFO] [stderr]    |
[INFO] [stderr] 55 | use std::collections::HashMap;
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: 1 warning emitted
[INFO] [stderr] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.01s
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/leetcoderusted-69d435d28802ff50
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/0001e_two_sum-fd846793bfb731e0
[INFO] [stdout] 
[INFO] [stdout] running 1 test
[INFO] [stdout] test tests::test_me ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/0021e_merge_2_sorted_lists-0c6f8078d2e3d20b
[INFO] [stdout] 
[INFO] [stdout] running 1 test
[INFO] [stdout] test tests::test_21 ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/0038_random_test-3bb05a7820f033f6
[INFO] [stdout] 
[INFO] [stdout] running 1 test
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/1304e_find_n_unique_int_sum_as_0-4d4405ac7d57c8db
[INFO] [stdout] test tests::test_12 ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] running 1 test
[INFO] [stdout] test tests::test_sol ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/1309e_decrypt_string_from_alpha_to_int_mapping-338725f3e6ff3244
[INFO] [stdout] 
[INFO] [stdout] running 1 test
[INFO] [stdout] test tests::test_sol ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/1313e_decompress_run_length_encoded_list-9e8603581036ca92
[INFO] [stdout] 
[INFO] [stdout] running 1 test
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/1317e_convert_integer_to_sum_of_two_nozero_integers-6bbda09df026ebe4
[INFO] [stdout] test tests::test_sol ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] running 1 test
[INFO] [stdout] test tests::test_sol ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/1323e_maximum_69_number-076dacd14d577fe8
[INFO] [stdout] 
[INFO] [stdout] running 1 test
[INFO] [stdout] test tests::test_sol ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/1331e_rank_transform_of_an_array-e4df090ca72bf7d4
[INFO] [stdout] 
[INFO] [stdout] running 1 test
[INFO] [stdout] test tests::test_sol ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/1337e_k_weakest_rows_in_a_matrix-09433fab188cc5a5
[INFO] [stdout] 
[INFO] [stdout] running 1 test
[INFO] [stdout] test tests::test_sol ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/1399e_count_largest_group-484b035769615a7b
[INFO] [stdout] 
[INFO] [stdout] running 1 test
[INFO] [stdout] test tests::test_sol ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/1486e_xor_in_array-46d39283e2f00ded
[INFO] [stdout] 
[INFO] [stdout] running 1 test
[INFO] [stdout] test tests::test_me ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/1502e_can_make_arithmetic_prog_from_seq-57d8c45d3402f5bc
[INFO] [stdout] 
[INFO] [stdout] running 1 test
[INFO] [stdout] test tests::test_sol ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/1507e_reformat_date-ef91925bf1ee2fa9
[INFO] [stdout] 
[INFO] [stdout] running 1 test
[INFO] [stdout] test tests::test_sol ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/1512e_number_of_good_pairs-b112dcbb967c566f
[INFO] [stdout] 
[INFO] [stdout] running 1 test
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/1523e_count_odd_numbers_in_an_interval_range-98794863922a33ca
[INFO] [stdout] test tests::test_sol ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] running 1 test
[INFO] [stdout] test tests::test_sol ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "9f6f35749abbc5f5eb052bec5f8215329b1d935ff5722d75bc9e106ce3d90ffd", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9f6f35749abbc5f5eb052bec5f8215329b1d935ff5722d75bc9e106ce3d90ffd", kill_on_drop: false }`
[INFO] [stdout] 9f6f35749abbc5f5eb052bec5f8215329b1d935ff5722d75bc9e106ce3d90ffd