{
  description = "Advent of Code 2024, but Nix";

  inputs = { nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable-small"; };

  outputs = { self, nixpkgs }:
    let
      inherit (nixpkgs) lib;
      utils = import ./utils.nix { inherit lib nixpkgs; };
    in {
      formatter.x86_64-linux = nixpkgs.legacyPackages.x86_64-linux.nixfmt;
    } // (builtins.mapAttrs
      (n: v: import "${./.}/${n}" { inherit lib nixpkgs utils; })
      (lib.filterAttrs (n: v:
        v == "directory" && (builtins.match "(day[[:digit:]]+)" n) != null)
        (builtins.readDir ./.)));
}