#include<bits/stdc++.h>
#include<stdio.h>
typedef long long ll;
typedef double llf;
#define mod 1000000007
#define cin1(a) scanf("%lld",&a)
#define cin2(a,b) scanf("%lld%lld",&a,&b)
#define cin3(a,b,c) scanf("%lld%lld%lld",&a,&b,&c)
#define cin4(a,b,c,d) scanf("%lld%lld%lld%lld",&a,&b,&c,&d)
#define cinc(x) scanf("%c",&x)
#define cinf(x) scanf("%lf",&x)
#define cins(x) scanf("%s",x)
#define cinl(x) getline(cin,x)
#define mp make_pair
#define pb push_back
ll fact[1000001],modfact[1000001];
void fs(ll &number)
{
	 bool negative=false;
    register ll c;
    number=0;
    c=getchar();
    if (c=='-')
    {
        negative=true;
        c=getchar();
    }
    for (;(c>47&&c<58);c=getchar())
        number=number*10+c-48;
    if (negative)
        number*=-1;
}
ll power(ll x,ll y)
{
	x=x%mod;
	ll res=1;
	while (y)
	{
		if (y&1)
			res=(res*x)%mod;
		x=(x*x)%mod;
		y>>=1;
	}
	return res;
}
void factorial()
{
	fact[0]=1;
	modfact[0]=power(1,mod-2)%mod;
	for(ll i=1;i<=1000000;i++)
	{
		fact[i]=(fact[i-1]*i)%mod;
		modfact[i]=(modfact[i-1]*power(i,mod-2))%mod;
	}
}
using namespace std;
int main()
{
	ios_base::sync_with_stdio;
	cin.tie(NULL);
	cout.tie(NULL);
	ll n;
    cin>>n;
    ll arr[n+1],arrsqr[n+1];
    for (ll i=1;i<=n;i++)
    {
        ll t;
        cin>>t;
        arr[i]=t+arr[i-1];
        arrsqr[i]=t*t+arrsqr[i-1];
    }
    ll maximum=-1000000000000;
    for (ll i=1;i<=n;i++)
    {
        ll sum=0;
        for (ll j=i;j<=n;j++)
        {
            sum=((arr[j]-arr[i-1])*(arr[j]-arr[i-1])-(arrsqr[j]-arrsqr[i-1]))/2;
            maximum=max(sum,maximum);
        }
    }
    cout<<maximum<<endl;
}