#include <fstream>

using namespace std;

ifstream fin("cmmdc.in");
ofstream fout("cmmdc.out");

int main(){
    int a, b, r;
    fin >> a >> b;
    while(b){
        r = a % b;
        a = b;
        b = r;
    }
    if(a > 1)
        fout << a;
    else
        fout << 0;

    return 0;
}