#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <string>
#include <cstring>
#include <sstream>
#include <cmath>
#include <vector>
#include <algorithm>


using namespace std;


int gcd(int a,int  b)
{
    return !b?a:gcd(b,a%b);
}


int main()
{

    int a=12,b=16;

    int res=gcd(a,b);

    cout<<res;


    return 0;
}