#include <fstream>
#include <iostream>
using namespace std;

int main() {
    ifstream fin("cmmdc.in");
    ofstream fout("cmmdc.out");

    int a, b;
    fin >> a >> b;

    while (a != b) {
        if (a > b) {
            a -= b;
        } else {
            b -= a;
        }
    }

    if (a == 1) {
        fout << 0;
    } else {
        fout << a;
    }
    return 0;
}