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