#用前缀和暴力求解，9/12的通过率

n = int(input())

l = list(map(int, input().split()))

for i in range(1, len(l)):

l[i] = l[i - 1] + l[i]

if n == 1:

print(l[0])

else:

dp = [l[0]]

for i in range(1, len(l)):

dp.append(l[i])

for j in range(i):

dp.append(l[i] - l[j])

print(max(dp))