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