#include<fstream>
using namespace std;
int main(){
    ifstream in("cmmdc.in");
    ofstream out("cmmdc.out");
    int a, b, r;
    in>>a>>b;
    r=a%b;
    while(r){
        a=b;
        b=r;
        r=a%b;
    }
    if(b<30000 && b!=1){
        out<<b;
    }
    if(b==1){
        out<<0;
    }
    in.close();
    out.close();
    return 0;
}