#include <fstream>

using namespace std;

ifstream fin ("cmmdc.in");
ofstream fout ("cmmdc.out");

int main()
{
    int a, b, r;
    fin >> a >> b;
    while(b)
    {
        r = a%b;
        a = b;
        b = r;
    }
    if(a == 1)
        fout << 0;
    else
        fout << a;
    return 0;
}