diff --git a/day25.peggy b/day25.peggy
new file mode 100644
index 0000000..8510541
--- /dev/null
+++ b/day25.peggy
@@ -0,0 +1,7 @@
+schemata = (lock / key)|.., "\n"|
+
+lock = "#####" "\n" rows:row+ { return {type: 'lock', rows, h: []}}
+
+key = rows:row+ { return { type: 'key', rows: rows.slice(0, -1), h: []}}
+
+row = @[#.]+ "\n"
diff --git a/day25.ts b/day25.ts
new file mode 100644
index 0000000..15ff583
--- /dev/null
+++ b/day25.ts
@@ -0,0 +1,45 @@
+import { type MainArgs, parseFile } from './lib/utils.ts';
+
+interface KeyLock {
+  type: 'key' | 'lock';
+  rows: string[][];
+  h: number[];
+}
+type Parsed = KeyLock[];
+
+function fits(key: number[], lock: number[]): boolean {
+  for (let i = 0; i < 5; i++) {
+    if (key[i] + lock[i] > 5) {
+      return false;
+    }
+  }
+  return true;
+}
+
+function part1(inp: Parsed): number {
+  for (const i of inp) {
+    for (let col = 0; col < 5; col++) {
+      let tot = 0;
+      for (let row = 0; row < i.rows.length; row++) {
+        if (i.rows[row][col] === '#') {
+          tot++;
+        }
+      }
+      i.h.push(tot);
+    }
+  }
+  let count = 0;
+  for (const key of inp.filter(({ type }) => type === 'key')) {
+    for (const lock of inp.filter(({ type }) => type === 'lock')) {
+      if (fits(key.h, lock.h)) {
+        count++;
+      }
+    }
+  }
+  return count;
+}
+
+export default async function main(args: MainArgs): Promise<[number]> {
+  const inp = await parseFile<Parsed>(args);
+  return [part1(inp)];
+}
diff --git a/inputs b/inputs
index cc618e3..3f1c03b 160000
--- a/inputs
+++ b/inputs
@@ -1 +1 @@
-Subproject commit cc618e35fc7c313f08404ebb9fb42ab5bce296d5
+Subproject commit 3f1c03bd92fe3f00d58224ba1f83802ddd1de045
diff --git a/test/day25.js b/test/day25.js
new file mode 100644
index 0000000..e9e4620
--- /dev/null
+++ b/test/day25.js
@@ -0,0 +1 @@
+export default [3397];