day 1

Signed-off-by: Amneesh Singh <natto@weirdnatto.in>

flake.nix

@@ -0,0 +1,31 @@
+{
+  description = "AoC 2023 in Haskell";
+
+  inputs = {
+    nixpkgs.url = github:nixos/nixpkgs/release-23.11;
+    utils.url = github:numtide/flake-utils;
+  };
+
+  outputs = { self, nixpkgs, utils }:
+    utils.lib.eachDefaultSystem
+      (system:
+        let
+          pkgs = import nixpkgs {
+            inherit system;
+          };
+          src = ./.;
+        in
+        with pkgs; {
+          devShells.default = mkShell {
+            buildInputs = [
+              ghc
+              haskell-language-server
+            ];
+          };
+          apps.default = {
+            type = "app";
+            program = "${ghc}/bin/runhaskell";
+          };
+        }
+      );
+}