#include <iostream>
#include <fstream>

using namespace std;

int main()
{
    int a,b,r;
    ifstream f("cmmdc.in");
    ofstream g("cmmdc.out");
    f>>a>>b;

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

    f.close();
    g.close();

    return 0;
}