#include <bits/stdc++.h>
using namespace std;
#define For(i,a,b) for(int i = a; i <= b; ++i)
signed main()
{
    #ifdef NICEGUODONG
        freopen("data.in","r",stdin);
    #endif
    int n;
    cin >> n;
    vector<int> a(n);
    For(i,1,n)
        cin >> a[i - 1];
    sort(a.begin(),a.end());
    int flag = 0;
    for(int i = 1; i < n; ++i){
        if(a[i] % a[0] != 0 || a[i] >= 2 * a[0] + 1){
            flag = 1;
            break;
        }
    }
    if(!flag)
        cout << a[0] << '\n';
    else
        cout << max((a[0] - 1) / 2,1);
    return 0;
}