#include <fstream>

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