#include <fstream>
using namespace std;

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

int GCD(int A, int B)
{
    while(B)
    {
        int R = A % B;
        A = B;
        B = R;
    }

    return A;
}

int main()
{
    int T;

        int A,B, CMMDC;
        fin>>A>>B;

        CMMDC = GCD(A,B) ;

        if(CMMDC == 1)
            CMMDC = 0;

        fout<<CMMDC<<"\n";

    return 0;
}