#-------------------------------------------------------------------------------
#  Euclid.py
#  Find the GCD of two positive integers by Euclid's algorithm
#
#  Try importing Euclid to another program, or into interactive mode.
#
#-------------------------------------------------------------------------------

def GCD(a, b):
   """ returns the GCD of two positive integers a and b """
   r = a%b
   # print(a, b, r)
   while r>0:
      a = b
      b = r
      r = a%b
      # print( a, b, r)
   return b

# main program ----------------------------------------------------------------

# This conditional statement allows us to import Euclid.py as a module without 
# running the main program.
if __name__=='__main__':

   print('Enter two positive integers')
   a = int(input('First: '))
   b = int(input('Second: '))
   print( 'GCD('+str(a)+', '+str(b)+') = '+str(GCD(a, b)) ) 

# end if