#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int main() {
    int n;
    cin >> n;
    vector <unsigned int> a(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }
    sort(a.begin(), a.end());
    unsigned int ans = 0;
    for (int i = a.size() - 1; i > 0; i--) {
        for (int j = i - 1; j >= 0; j--) {
            if (a[i] + a[j] > ans) {
                ans = a[i] + a[j];
            }
            else {
                break;
            }
        }
    }
    cout << ans;
    return 0;
}