#include <bits/stdc++.h>
#define pb push_back
#define mp make_pair
using namespace std;
typedef long long ll;
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    ll n,a1,a2,a3;
    cin>>n;
    vector<ll>a(n);
    for(a1=0;a1<n;++a1){
        cin>>a[a1];
    }
    ll ans=0;
    for(a1=0;a1<n;++a1){
        for(a2=a1;a2<n;++a2){
            ll sum=0,pp=0;
            for(a3=a1;a3<=a2;++a3){
                sum+=a[a3];
            }
            for(a3=a1;a3<a2;++a3){
                sum-=a[a3];
                pp+=a[a3]*sum;
                
            }
            ans=max(ans,pp);
        }
    }
    cout<<ans;
	return 0;
}