# Uses python3
import sys


def getGCD(a, b):
	if b == 0:
			return a
	if b > a:
		return getGCD(b, a)
	else:
		return getGCD(b, a % b)


if __name__ == '__main__':
    entryNumbers = sys.stdin.read()
    tokens = entryNumbers.split()
    a = int(tokens[0])
    b = int(tokens[1])
    print(getGCD(a, b))