#include <stdio.h>

int cmmdc (int a, int b) {
	if (b == 0) return a;
	
	return cmmdc(b, a%b);
}

int main (void) {
	freopen("cmmdc.in", "r", stdin);
	freopen("cmmdc.out", "w", stdout);
	
	int a, b;
	scanf("%d %d", &a, &b);
	
	if (a < b) {
		int temp = a;
		a = b;
		b = temp;
	}
	
	int c = cmmdc(a, b);
	printf("%d", (c != 1) ? c : 0);

	return 0;
}