#include<iostream>
#include<fstream>

using namespace std;

long int a, b, rest;
ifstream f("cmmdc.in");
ofstream g("cmmdc.out");

int main() {

	f >> a >> b;
	while (b != 0) {
		rest = a % b;
		a = b;
		b = rest;
	}
	if (a == 1) {
		g << 0;
	}
	else {
		g << a;
	}

	return 0;
}