#!/bin/python3

import sys

def largestValue(A):
    m_s = 0
    pprev = 0
    prev_p = 0
    prev_n = 0
    prev_sum = 0
    neg_sum = 0
    pos_sum = 0
    final_sum = 0
    for i in A:
        if i < 0 :
            pprev = final_sum
            if final_sum > 0:
                prev_sum = 0
                prev_p = 0
                prev_n = 0
                final_sum = final_sum + pos_sum * i + neg_sum * i
                neg_sum += i
            else:
                prev_sum = 0
                neg_sum = 0
                pos_sum = 0
                final_sum = prev_sum 
                prev_sum = 0
                prev_p = 0
                prev_n = 0
                continue
        else:
            final_sum += pos_sum *i + neg_sum *i
            prev_sum += prev_p*i+prev_n*i
            prev_p+=i
            pos_sum += i
            m_s = max(final_sum, m_s)
    return m_s
                
            
if __name__ == "__main__":
    n = int(input().strip())
    A = list(map(int, input().strip().split(' ')))
    result = largestValue(A)
    print(result)