#include <fstream>

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

    return 0;
}