#include <fstream>
using namespace std;
ifstream fin ("cmmdc.in");
ofstream fout ("cmmdc.out");
int a, b, r;
int main()
{
    fin>>a>>b;
    while(b!=0)
    {
        r=a%b;
        a=b;
        b=r;
    }
    if(a==1)
        fout<<0;
    else fout<<a;

    return 0;
}