"""File:      recursive_sum.py
   Purpose:   Find the sum of the first n positive integers using recursion

   Run:       python recursive_sum.py

   Input:     A positive int n
   Output:    The sum of the first n positive integers
"""
def rsum(val):
   """ Use recursion to find the sum 1 + 2 + . . . + val"""
   if val == 1:
      return val
   else:
      sum = val + rsum(val-1)
      return sum

val = int(raw_input("Enter a whole number >= 1\n   "))
sum = rsum(val)
print "The sum of the first", val, "whole numbers is", sum