#include <stdio.h>

long long a, b;

long long cmmdc (long long a, long long b)
{
	if (!b) return a;
	return cmmdc (b, a%b);
}

int main ()
{
	freopen ("euclid2.in", "r", stdin);
	freopen ("euclid2.out", "w", stdout);

	scanf ("%lld %lld", &a, &b);

	long long R = cmmdc (a, b);
	printf ("%lld\n", (int) R);
	return 0;
}