n = int(input())
Q = list(map(int, input().split()))

if n < 2:
    print(0)
else:
    max_e = Q[0] * Q[1]
    dp_prev = max_e
    max_pos = -float('inf')
    max_pos_val = 0
    min_neg = float('inf')
    min_neg_val = 0
    
    if Q[1] > 0:
        max_pos = Q[1]
        max_pos_val = max(dp_prev, 0)
    else:
        min_neg = Q[1]
        min_neg_val = max(dp_prev, 0)
    
    for i in range(2, n):
        current_q = Q[i]
        candidate_prev = current_q * Q[i-1]
        candidate_cont = dp_prev + candidate_prev
        
        if current_q > 0:
            candidate = current_q * max_pos + max_pos_val if max_pos != -float('inf') else -float('inf')
        else:
            candidate = current_q * min_neg + min_neg_val if min_neg != float('inf') else -float('inf')
        
        current_dp = max(candidate, candidate_cont, candidate_prev)
        max_e = max(max_e, current_dp)
        
        max_contrib = max(current_dp, 0)
        if current_q > max_pos or (current_q == max_pos and max_contrib > max_pos_val):
            max_pos = current_q
            max_pos_val = max_contrib
        if current_q < min_neg or (current_q == min_neg and max_contrib > min_neg_val):
            min_neg = current_q
            min_neg_val = max_contrib
        
        dp_prev = current_dp
    
    print(max_e)