diff --git a/haskell/Main.hs b/haskell/Main.hs
index 47adfa7..bdd1d98 100644
--- a/haskell/Main.hs
+++ b/haskell/Main.hs
@@ -8,6 +8,7 @@ import Puzzle
 import Puzzles.Day1 qualified as Day1
 import Puzzles.Day2 qualified as Day2
 import Puzzles.Day3 qualified as Day3
+import Puzzles.Day4 qualified as Day4
 import Test.Tasty
 import Test.Tasty.Golden (goldenVsString)
 import Test.Tasty.Ingredients.ConsoleReporter
@@ -23,6 +24,7 @@ main =
                 [ Day1.puzzle
                 , Day2.puzzle
                 , Day3.puzzle
+                , Day4.puzzle
                 ]
                     <&> \Puzzle{number, parser, parts} ->
                         let
diff --git a/haskell/Puzzles/Day4.hs b/haskell/Puzzles/Day4.hs
new file mode 100644
index 0000000..d416801
--- /dev/null
+++ b/haskell/Puzzles/Day4.hs
@@ -0,0 +1,14 @@
+module Puzzles.Day4 (puzzle) where
+
+import Puzzle
+
+puzzle :: Puzzle
+puzzle =
+    Puzzle
+        { number = 4
+        , parser = pure ()
+        , parts =
+            [ \() ->
+                "TODO"
+            ]
+        }
diff --git a/haskell/aoc.cabal b/haskell/aoc.cabal
index 6e6faf8..07ada31 100644
--- a/haskell/aoc.cabal
+++ b/haskell/aoc.cabal
@@ -13,6 +13,7 @@ executable aoc
         Puzzles.Day1
         Puzzles.Day2
         Puzzles.Day3
+        Puzzles.Day4
     default-language: GHC2024
     default-extensions:
         BlockArguments
diff --git a/inputs/examples/4 b/inputs/examples/4
new file mode 100644
index 0000000..8209399
--- /dev/null
+++ b/inputs/examples/4
@@ -0,0 +1,10 @@
+..@@.@@@@.
+@@@.@.@.@@
+@@@@@.@.@@
+@.@@@@..@.
+@@.@@@@.@@
+.@@@@@@@.@
+.@.@.@.@@@
+@.@@@.@@@@
+.@@@@@@@@.
+@.@.@@@.@.
diff --git a/inputs/private b/inputs/private
index 69a0d6c..7d234e9 160000
--- a/inputs/private
+++ b/inputs/private
@@ -1 +1 @@
-Subproject commit 69a0d6cdd7aa47dedb9b6653a27bd5e717d766fb
+Subproject commit 7d234e9ef9f6a1ea8b263e2a2e9b936eba1fcc46
diff --git a/outputs/examples/4/1 b/outputs/examples/4/1
new file mode 100644
index 0000000..ca7bf83
--- /dev/null
+++ b/outputs/examples/4/1
@@ -0,0 +1 @@
+13
\ No newline at end of file