diff --git a/2020/day10.py b/2020/day10.py
new file mode 100644
index 0000000..be575ac
--- /dev/null
+++ b/2020/day10.py
@@ -0,0 +1,34 @@
+import sys
+
+
+def main():
+    lines = sorted([int(line.rstrip()) for line in sys.stdin])
+    
+    # Part 1
+    diffs = {1: 0, 3: 0}
+    jojo = 0
+    for v in lines:
+        d = v - jojo
+        diffs[d] += 1
+        jojo = v
+    print("Part 1:", diffs[1] * (diffs[3] + 1))
+
+    # Part 2 - yes recursion is fine but have you tried caching your damn values
+    print("Part 2:", rec(0, lines, 0, len(lines), {}))
+
+
+def rec(i, l, n, z, c):
+    if i >= z - 1:
+        return 1
+    if (p := c.get((i, n))) is not None:
+        return p
+    p = 0
+    for ni, nv in enumerate(l[i:i+3]):
+        if n < nv <= n + 3:
+            p += rec(i + ni + 1, l, nv, z, c)
+    c[(i, n)] = p
+    return p
+
+
+if __name__ == "__main__":
+    main()
diff --git a/2020/day9.py b/2020/day9.py
index d733bf2..13dae44 100644
--- a/2020/day9.py
+++ b/2020/day9.py
@@ -1,9 +1,9 @@
 import itertools
+import sys
 
 
 def main():
-    with open("day9.txt", "rt") as f:
-        series = [int(line.rstrip()) for line in f.readlines()]
+    series = [int(line.rstrip()) for line in sys.stdin]
     
     # Part 1
     frame_len = 25