#include<bits/stdc++.h>
#define MOD 1000000007
#define loop(i,a,b) for(long long int i=a;i<b;i++)
#define loopm(i,a,b) for(long long int i=a;i>=b;i--)
#define sloop(i,a,b,step) for(long long int i=a;i<b;i+=step)
#define sloopm(i,a,b,step) for(long long int i=a;i>=b;i-=step)
#define init(arr,val) memset(arr,val,sizeof(arr))
#define pb(a) push_back(a)
#define mp(a,b) make_pair(a,b)
typedef long long int ll;

using namespace std;
vector<ll> v;

void kadane(ll arr[], ll n)
{
    
    ll max_so_far = 0;

    ll max_ending_here = 0;

    
    ll start = 0, end = 0;

    
    ll beg = 0;

    
    for (ll i = 0; i < n; i++)
    {
        max_ending_here = max_ending_here + arr[i];

        if (max_ending_here < 0)
        {
            max_ending_here = 0;    
            beg = i + 1;
        }

        if (max_so_far < max_ending_here)
        {
            max_so_far = max_ending_here;
            start = beg;
            end = i;
        }
    }
    for (ll i = start; i <= end; i++)
    v.pb(arr[i]);
}

int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);

ll n,ans=0;
cin>>n;
ll arr[n];
loop(i,0,n)
cin>>arr[i];
kadane(arr,n);
ll len=v.size();
loop(i,0,len-1)
{
	loop(j,i+1,len)
	ans+=(v[i]*v[j]);
}
cout<<ans<<"\n";



return 0;
}