diff --git a/10/10.py b/10/10.py
index 028772f..643dcd8 100644
--- a/10/10.py
+++ b/10/10.py
@@ -6,7 +6,7 @@ data = [list(map(int, x)) for x in data]
 
 def make_bound(data):
     N = len(data)
-    M = len(data)
+    M = len(data[0])
     def bound(i, j):
         return 0<=i<N and 0<=j<M
     return bound
@@ -23,6 +23,7 @@ def f1(data, collect=set):
             yield from score(i+di, j+dj, x+1)
     zeroes = [(i, j) for i, l in enumerate(data) for j, x in enumerate(l) if x==0]
     bound = make_bound(data)
+    
     d = [(1,0), (0,1), (-1,0), (0,-1)]
     return sum(1 for z in zeroes for _ in collect(score(*z)))
 print(f1(data))
diff --git a/11/11.py b/11/11.py
new file mode 100644
index 0000000..0887843
--- /dev/null
+++ b/11/11.py
@@ -0,0 +1,28 @@
+from collections import defaultdict
+
+data = list(map(int, open("input.txt").read().strip().split()))
+
+def rules(x):
+    if x==0:
+        return [1]
+    s = str(x)
+    if len(s)%2==0:
+        return [int(s[:len(s)//2]), int(s[len(s)//2:])]
+    return [x*2024]
+
+
+def f(data, n):
+    d = defaultdict(int)
+    for x in data:
+        d[x] += 1
+    for i in range(n):
+        t = defaultdict(int)
+        for j, k in d.items():
+            for x in rules(j):
+                t[x] += k
+        d = t
+    return sum(d.values())
+
+assert f(data, 25)==203609
+print(f(data, 25))
+print(f(data, 75))