UCLN C++

#include <bits/stdc++.h>
using namespace std;
int a[15], n,res;

void nhap()
{
    cin >> n;
    for (int i = 1; i <= n; i++)
        cin >> a[i];
}
int gcd(int x, int y)
{
    while (y != 0)
    {
        int t = x % y;
        x = y;
        y = t;
    }
    return x;
}
void giai()
{
    res=a[1];
    for(int i=2;i<=n;i++)
        res=gcd(res,a[i]);
    cout<<res;
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);cout.tie(0);
    freopen("ucln.inp","r",stdin);
    freopen("ucln.out","w",stdout);
    nhap();
    giai();
}