#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <climits>
using namespace std;


int main() {
    int n, i, j, k, l;
    cin >> n;
    int a[n];
    for(i=0;i<n;i++)
        cin >> a[i];
    int res = INT_MIN;
    int p[n-1], s[n-1];
    for(i=0;i<n-1;i++){
       for(j=i;j<n;j++){
           p[0] = a[i]*a[i+1];
           s[0] = a[i]+a[i+1];
           l = 1;
           for(k=i+2;k<=j;k++){
               p[l] = (s[l-1]*a[k])+p[l-1];
               s[l] = s[l-1] + a[k];
               l++;
           }
           res = max(res, p[l-1]);
       } 
    }
    cout << res << endl;
    return 0;
}