#include <bits/stdc++.h>

using namespace std;

long largestValue(vector <int> A) {
    // dict[sum Xi] = min sum Xi^2
    unordered_map<long, long> dict;
    long rtn = 0;
    dict[0] = 0;
    for (int x : A) {
        unordered_map<long, long> curr;
        for (auto it = dict.begin(); it != dict.end(); ++it) {
            long key = it->first + x;
            long val = it->second + x * x;
            if (curr.find(key) == curr.end()) curr[key] = val;
            else curr[key] = min(curr[key], val);
        }
        for (auto it = curr.begin(); it != curr.end(); ++it) {
            if (dict.find(it->first) == dict.end()) dict[it->first] = it->second;
            else dict[it->first] = min(dict[it->first], it->second);
            long curr_val = (it->first * it->first - dict[it->first]) / 2;
            rtn = max(rtn, curr_val);
        }
    }
    return rtn;
}

int main() {
    int n;
    cin >> n;
    vector<int> A(n);
    for(int A_i = 0; A_i < n; A_i++){
       cin >> A[A_i];
    }
    long result = largestValue(A);
    cout << result << endl;
    return 0;
}