/*
*/

//#pragma GCC optimize("O3")
#define _CRT_SECURE_NO_WARNINGS
#include <fstream>
#include <iostream>
#include <string>
#include <complex>
#include <math.h>
#include <set>
#include <vector>
#include <map>
#include <queue>
#include <stdio.h>
#include <stack>
#include <algorithm>
#include <list>
#include <ctime>

#include <memory.h>
#include <assert.h>

#define y0 sdkfaslhagaklsldk

#define y1 aasdfasdfasdf
#define yn askfhwqriuperikldjk
#define j1 assdgsdgasghsf
#define tm sdfjahlfasfh
#define lr asgasgash
#define norm asdfasdgasdgsd
#define have adsgagshdshfhds
#define ends asdgahhfdsfshdshfd

#define eps 1e-8
#define M_PI 3.141592653589793
#define bsize 512

#define ldouble long double
using namespace std;

#define bs 1000000007

const int N = 600031;

int n,ar[N];
long long ans,S[N],S2[N],S3[N];

void update(int l,int r){
	long long here=(S[r]-S[l-1])*(S[r]-S[l-1])-(S2[r]-S2[l-1]);
	ans=max(ans,here);
}

set<pair<long long, long long> > se;
set<pair<long long, long long> > ::iterator it;
set<pair<long long, long long> > se2;
set<pair<long long, long long> > se3;

int main(){
//	freopen("apache.in","r",stdin);
//	freopen("apache.out","w",stdout);
	//freopen("input.txt", "r", stdin);
	//freopen("output.txt", "w", stdout);
	ios_base::sync_with_stdio(0);
//	cin.tie(0);

	cin>>n;
	for (int i=1;i<=n;i++){
		cin>>ar[i];
		S[i]=S[i-1]+ar[i];
		S2[i]=S2[i-1]+1ll*ar[i]*ar[i];
		S3[i]=S[i]*S[i]-S2[i];
	}

	if (n<=5000){
		for (int l=1;l<=n;l++){
			for (int r=l;r<=n;r++){
				update(l,r);
			}
		}
		cout<<ans/2<<endl;
		return 0;
	}

	se.insert(make_pair(0,0));
	se2.insert(make_pair(0,0));
	se3.insert(make_pair(0,0));
	for (int i=1;i<=n;i++){
		int cnt=0;
		for (it=se.begin();it!=se.end();it++)
		{
			++cnt;
			if (cnt>50)
				break;
			int id=(*it).second;
			update(id,i);
		}
		cnt=0;

		for (it=se.end();;--it){
			if (it==se.begin())
				break;
			if (it==se.end())
				continue;
			++cnt;
			if (cnt>50)
				break;
			int id=(*it).second;
			update(id,i);
		}

		cnt=0;
		/// cp
		for (it=se2.begin();it!=se2.end();it++)
		{
			++cnt;
			if (cnt>50)
				break;
			int id=(*it).second;
			update(id,i);
		}
		cnt=0;

		for (it=se2.end();;--it){
			if (it==se2.begin())
				break;
			if (it==se2.end())
				continue;
			++cnt;
			if (cnt>50)
				break;
			int id=(*it).second;
			update(id,i);
		}

		// cp2
		cnt=0;
		/// cp
		for (it=se3.begin();it!=se3.end();it++)
		{
			++cnt;
			if (cnt>50)
				break;
			int id=(*it).second;
			update(id,i);
		}
		cnt=0;

		for (it=se3.end();;--it){
			if (it==se3.begin())
				break;
			if (it==se3.end())
				continue;
			++cnt;
			if (cnt>50)
				break;
			int id=(*it).second;
			update(id,i);
		}
		se.insert(make_pair(S[i],i));
		se2.insert(make_pair(S2[i],i));
		se3.insert(make_pair(S3[i],i));
	}

	cout<<ans/2<<endl;

//	cin.get(); cin.get();
	return 0;
}