diff --git a/day04.ua b/day04.ua
new file mode 100644
index 0000000..a89c2eb
--- /dev/null
+++ b/day04.ua
@@ -0,0 +1,29 @@
+$ Card 1: 41 48 83 86 17 | 83 86  6 31 17  9 48 53
+$ Card 2: 13 32 20 16 61 | 61 30 68 82 17 32 24 19
+$ Card 3:  1 21 53 59 44 | 69 82 63 72 16 21 14  1
+$ Card 4: 41 92 73 84 69 | 59 84 76 51 58  5 54 83
+$ Card 5: 87 83 26 28 32 | 88 30 70 12 93 22 82 36
+$ Card 6: 31 18 13 56 72 | 74 77 10 23 35 67 36 11
+TestInput ←
+
+Parse ← ∩(⊜parse≠@ .⊔)⍘⊟⊏1_3 ⊢regex "((\\d+\\s+)+)\\|((\\s+\\d+)+)"
+
+PartIPre ← ⌊ⁿ:2-1/+♭⊞=Parse
+PartIPost ← /+
+
+PartIIPre ← /+♭⊞=Parse
+PartIIPost ← (
+  ⊃(∘|+1⊚⧻)
+  ⊙⊙0
+  ∧(
+    ⊃(⊙⊢|⋅(↘1)|⋅(+⊢))
+    ⬚0+×+1⊚
+  )
+  ;
+)
+
+PartIPost ⊜PartIPre ≠@\n. TestInput
+PartIIPost ⊜PartIIPre ≠@\n. TestInput
+
+PartIPost ⊜PartIPre ≠@\n. &fras "day04.in"
+PartIIPost ⊜PartIIPre ≠@\n. &fras "day04.in"