#include <fstream>

using namespace std;

ifstream ci ("cmmdc.in");
ofstream co ("cmmdc.out");

int main()
{
    int a, b, p;
    ci >> a >> b;
    if (b>a)
    {
        p=a;
        a=b;
        b=p;
    }
    while (b)
    {
        p=a%b;
        a=b;
        b=p;
    }
    if (a==1)
    {
        a=0;
    }
    co << a;
    return 0;
}