#include <iostream>
#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;


}