#File: ChapterRecursion/gcd.py
""" gcd(n,m) = greatest common divder of two integers
    EUCLID's algorithm
first int? 60
second int? 54
computing gcd(60, 54)
computing gcd(54, 6)
computing gcd(6, 0)
gcd( 60, 54 ) = 6
"""
def gcd( a, b ):
    print( "computing gcd(%d, %d)" % (a, b))
    if b == 0 :
        return a
    else:
        return gcd( b, a % b )

def main():
    while True:
        a = int(input( "first int? " ))
        b = int(input( "second int? " ))
        if ( a == 0 or b == 0):
            break;
        print("gcd( %d, %d ) = %d" % (a, b, gcd( a,b ) ))
        
main()