diff --git a/main.py b/main.py
old mode 100644
new mode 100755
index 22f6adb4516ad40f6633305ed8266cb96151bfbe..6b0581f71996a2099d3abbdcc62bd6aa08bb3fa2
--- a/main.py
+++ b/main.py
@@ -1,3 +1,4 @@
+#!/usr/bin/python3
 def NFact135():
     def fact(x):
         _fact = 1
diff --git a/nonrecfib.py b/nonrecfib.py
old mode 100644
new mode 100755
index 244fb825b2f9b64bef22791a3fc67961b8cd6ded..d2cafc5bfccc18c61a8aa4ade9e563bc5e21bd6e
--- a/nonrecfib.py
+++ b/nonrecfib.py
@@ -1,3 +1,4 @@
+#!/usr/bin/python3
 """Document Comment."""