//http://www.infoarena.ro/problema/cmmdc

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

int euclid(unsigned a, unsigned b)
{
    int c;
    while (b) {
        c = a % b;
        a = b;
        b = c;
    }
    return a;
}
int main()
{
    unsigned a,b;
    ifstream f("cmmdc.in");
    ofstream g("cmmdc.out");
    f>>a;f>>b;
    if(euclid(a,b)==1)
       g<<"0";
    else
    g<<euclid(a,b);
}