#include <iostream>
#include <fstream>
using namespace std;
ifstream f("cmmdc.in");
ofstream g("cmmdc.out");
int main()
{
    int a, b;
    f>>a>>b;
    while(b!=0)
    {
        int r=a%b;
        a=b;
        b=r;

    }
    if(a!=1)
        g<<a;
    else
        g<<0;
    return 0;
}