diff --git a/2020/day9.py b/2020/day9.py
new file mode 100644
index 0000000..d733bf2
--- /dev/null
+++ b/2020/day9.py
@@ -0,0 +1,32 @@
+import itertools
+
+
+def main():
+    with open("day9.txt", "rt") as f:
+        series = [int(line.rstrip()) for line in f.readlines()]
+    
+    # Part 1
+    frame_len = 25
+    for i in range(len(series) - frame_len):
+        frame = series[i : i + frame_len]
+        n = series[i + frame_len]
+        for a, b in itertools.combinations(frame, 2):
+            if a + b == n:
+                break
+        else:
+            print("Invalid N:", n)
+            break
+
+    # Part 2
+    for i in range(len(series)):  # what is indexerror when you know it breaks
+        for j in range(1, len(series)):
+            frame = series[i : i + j + 1]
+            if (s := sum(frame)) == n:
+                print("Answer:", min(frame) + max(frame))
+                return
+            elif s > n:
+                break
+
+
+if __name__ == "__main__":
+    main()