#include<bits/stdc++.h>
#define re          return
#define ll          long long
#define pb          push_back
#define mp          make_pair
#define pii         pair<int,int>
#define vi          vector<int>
#define all(a)      (a).begin(),(a).end()
#define F           first
#define S           second
#define hell        1000000007
#define endl        '\n'
#define rep(i,a,b)  for (__typeof(b) i=(a)-((a)>(b));i!=(b)-((a)>(b));i+=1-2*((a)>(b)))
#define PI            3.141592653589793l
#define fill(c,val) memset(c,val,sizeof(c))
#define LB lower_bound
#define UB upper_bound
#define bsa(v,n,a) binary_search(v,v+n,a)
#define bsv(v,a) binary_search(v.begin(),v.end(),a)
using namespace std;
int maxSubArraySum(int a[], int size)
{
	 int n=size;
    int max_so_far = INT_MIN, max_ending_here = 0,
       start =0, end = 0, s=0;
 
    for (int 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;
        }
    }
          vector<long> v;
        for(int i=start-1;i<end-2;i++){
   	  for(int j=i+1;j<end;j++){
   	  	    v.pb(a[i]*a[j]);
		 }
    }
    vector<long int> max_ending;
        max_ending.resize(n);
        max_ending[0]=v[0];
        for(int i=1;i<n;i++){
            max_ending[i]=max(max_ending[i-1]+v[i],v[i]);
        }
       ll res=INT_MIN;
	  for(int i=0;i<n;i++){
	  	if(res<max_ending[i])
	  	res=max_ending[i];
	  }  
	  return res;
}
int main(){
	/*ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);*/
	int cnt=0,flag=0,flag1=0,ans=0,sum=0;
	int t=1;
	//cin>>t;
	while(t--){
	  int p;
	  cin>>p;
	  int a[p];
	 for(int i=0;i<p;i++){
	 	cin>>a[i];
	 }
    //sort(a,a+n);
       cout<<maxSubArraySum(a,p);
   }
    return 0;
}