#include <iostream>

using namespace std;

int main()
{
    int x, y;
    cin >> x >> y;
        while (x>0 && y>0)
        {
            if (x>y)
            {
                x=x-y;
            }
            else
            {
                y=y-x;
            }
        }
        if (x<=0)
            cout << y;
        else
            cout << x;
        return 0;

}