#include <iostream>
#include <fstream>
using namespace std;


int main()

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

        d=a%b;
        a=b;
        b=d;
    }
    if(a==1)
        g<<"0";
    else
        g<<a;

    return 0;
}