diff --git a/day9/day9.py b/day9/day9.py
index 1bef492..3a6fa48 100644
--- a/day9/day9.py
+++ b/day9/day9.py
@@ -1,5 +1,7 @@
 def part1():
-    file = open("input.txt")
+    file = open("input_test.txt")
+
+    preamble_length = 5
 
     for line in file:
         pass