#include <iostream>
#include <fstream>
using namespace std;
ifstream in("cmmdc.in");
ofstream out("cmmdc.out");
int main() {
        int a, b, r = 1, ac, bc;
        in >> a >> b;

        ac = a;
        bc = b;

        while (r) {
                r = a % b;
                a = b;
                b = r;
        }

        out << (a == 1 && ac != bc ? 0 : a);
        return 0;
}