#include <fstream>

using namespace std;

ifstream in("cmmdc.in");
ofstream out("cmmdc.out");
int main()
{
    int a,b,r;
    in>>a>>b;
    while(b)
    {
        r=a%b;
        a=b;
        b=r;
    }
    if(a==1)
        a=0;
    out<<a;
        return 0;
}