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