#include<bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define MAX 1000000007
using namespace std;
vector<ll> v;
void maxSubArraySum(ll a[], ll size)
{
    ll max_so_far = INT_MIN, max_ending_here = 0,
       start =0, end = 0, s=0;
 
    for (ll i=0; i< size; i++ )
    {
        max_ending_here += a[i];
 
        if (max_so_far < max_ending_here)
        {
            max_so_far = max_ending_here;
            start = s;
            end = i;
        }
 
        if (max_ending_here < 0)
        {
            max_ending_here = 0;
            s = i + 1;
        }
    }
    ll i,j;
    for(i=start;i<=end;++i) {
        v.pb(a[i]);
    }
    ll nn=end-start+1;
    ll x=0;
    for(i=0;i<nn-1;++i) {
        for(j=i+1;j<nn;++j) {
            x+=v[i]*v[j];
        }
    }
    cout<<x;
   // cout << "Maximum contiguous sum is "<< max_so_far << endl;
    //cout << "Starting index "<< start<< endl << "Ending index "<< end << endl;
}

int main() {
	ll n,i,a[1000005];
	cin>>n;
	for(i=0;i<n;++i) {
		cin>>a[i];
	}
	maxSubArraySum(a,n);
    return 0;
}