#!/bin/python3
import sys
def find(A):
    arraysum = sum(A)
    sq = arraysum*arraysum
    s = 0
    for i in A:
        s = s+(i*i)
    return ((sq-s)//2)

def largestValue(A):
    s= 0 
    maxi = -10**10
    #mul = 1
    l=[]
    for i in range(n):
        if s+A[i]<0:
            s=0
            l=[]
        else:
            s=s+A[i]
            l.append(A[i])
            sumi = 0
            sumi = find(l)
            
            #for j in range(len(l)):
                #for k in range(j+1,len(l)):
                    #if j!=k:
                    #sumi = sumi + l[j]*l[k]
            #if (i==4):
             #   print(sumi)
            #print(l)
            if maxi<sumi:
               # print(l)
                maxi = sumi
            #print(i)
    #print(l)
    return maxi
    # Return the largest value of any of A's nonempty subarrays.

if __name__ == "__main__":
    n = int(input().strip())
    A = list(map(int, input().strip().split(' ')))
    result = largestValue(A)
    print(result)