#include <fstream>
using namespace std;
ifstream fi("cmmdc.in");
ofstream fo("cmmdc.out");

int main()
{
    int a, b, r;
    fi>>a>>b;
    while (b != 0)
    {
        r = a%b;
        a = b;
        b = r;
    }
    if (a == 1)
        fo<<0;
    else
        fo<<a;
    fi.close();
    fo.close();
    return 0;
}