Adopted new convention from template

src/Python/Problems001-050/Problem003.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python3
+#!/usr/bin/env python
 """
 Created on 18 Mar 2017
 
@@ -17,8 +17,9 @@ def compute():
     """
     The prime factors of 13195 are 5, 7, 13 and 29.
 
-    What is the largest prime factor of the number 600851475143 ?
+    What is the largest prime factor of the number 600851475143?
     """
+
     ans = 600851475143
     factor = 2
     while factor * factor < ans:
@@ -30,5 +31,4 @@ def compute():
 
 
 if __name__ == "__main__":
-
-    print(f"Result for problem 3: {compute()}")
+    print(f"Result for problem 3 is {compute()}")