#include <bits/stdc++.h>

using namespace std;

int n;
int start=0,en=0;
long a[1000005];

void maxSubArraySum()
{
    int max_so_far = INT_MIN, max_ending_here = 0,
       start =0, en = 0, s=0;
 
    for (int i=0; i< n; i++ )
    {
        max_ending_here += a[i];
 
        if (max_so_far < max_ending_here)
        {
            max_so_far = max_ending_here;
            start = s;
            en = i;
        }
 
        if (max_ending_here < 0)
        {
            max_ending_here = 0;
            s = i + 1;
        }
    }
   //cout<<start<<" "<<en<<endl;
     long ans=0;
    long p[n]={0};
    
    p[en]=a[en];
    for(int i=en-1;i>=start;i--){
        p[i]=a[i]+p[i+1];
    }
   /* for(int i=start;i<=en;i++)
        cout<<p[i]<<" ";*/
    for(int i=start;i<en;i++){
        ans+=a[i]*p[i+1];
        //cout<<ans<<" ";
    }
   cout<< ans;
}

void largestValue() {
    maxSubArraySum();
    
   
}

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