diff --git a/fib.py b/fib.py
index 421cfab..d03225d 100644
--- a/fib.py
+++ b/fib.py
@@ -6,9 +6,14 @@
 Negative numbers should return None
 """
 def fibonacci(position):
-  if(position == 1 or position == 2):
-    return 1
-  return fibonacci(position - 1) + fibonacci(position - 2)
+if position < 0:
+return None
+elif position == 0:
+return 0
+elif position == 1:
+return 1
+else:
+return fibonacci(position - 1) + fibonacci(position - 2)