#include <iostream>
#include <fstream>

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

long long a,b;

void cmmdc(long long a, long long b)
{
    long long c;
    while (a!=b)
    {
        if(a>b) a=a-b;
        if(a<b) b=b-a;
    }
    if (a==1) fout<<0;
    else fout<<a;
}

int main()
{
    fin>>a;
    fin>>b;
    cmmdc(a,b);

}