#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(a>b)
        a = a - b;
        else
        b = b - a;
    }
    if (a == 1)
    g << "0";
    else
    g << a;
    return 0;
}