#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<cctype>
#include<cstdlib>
#include<algorithm>
#include<bitset>
#include<vector>
#include<list>
#include<deque>
#include<queue>
#include<map>
#include<set>
#include<stack>
#include<cmath>
#include<sstream>
#include<fstream>
#include<iomanip>
#include<ctime>
#include<complex>
#include<functional>
#include<climits>
#include<cassert>
#include<iterator>
#include<unordered_set>
#include<unordered_map>

using namespace std;


vector<long long int> v1;
vector<long long int> v2;
int main() {
	int n;
	cin >> n;
	for (int i = 0; i < n; i++) {
		int a;
		scanf("%d", &a);
		v1.push_back(0);
		v2.push_back(0);
		if (a > 0) {
			v1[i] = a;
		}
		else {
			v2[i] = -a;
		}
	}
	long long int way = LLONG_MIN;
	for (int j = 0; j < v2.size(); j++) {
		long long int sum1 = 0;
		long long int self1 = 0;
		long long int sum2 = 0;
		long long int self2 = 0;
		for (int i = j; i < v1.size(); i++) {
			sum1 += v1[i];
			self1 += v1[i] * v1[i];
			sum2 += v2[i];
			self2 += v2[i] * v2[i];
			long long int ans = 0;
			ans += (sum1*sum1 - self1) / 2LL;
			ans += (sum2*sum2 - self2) / 2LL;
			ans -= sum1*sum2;
			way = max(way, ans);
		}
		if (clock() / (double)(CLOCKS_PER_SEC)>1.7)break;
	}
	printf("%lld\n", way);
	return 0;
}