#include <iostream>
#include<fstream>
using namespace std;
ifstream in ("cmmdc.in");
ofstream out ("cmmdc.out");
int main()
{
    int b, a, r;
    in>>a>>b;
    while(b)
    {
        r=a%b;
        a=b;
        b=r;
    }
    if(a==1)
        out<<0;
    else
    out<<a;
    return 0;
}