$O(n)算法$

n = int(input())
l = [0]+list(map(int,input().split()))
f = [0 for i in range(n+10)]
maxn = -10000
for i in range(1,n+1):
    if f[i-1]+l[i]>f[i]:
        f[i] = f[i-1]+l[i]
    maxn = max(maxn,f[i])
print(maxn)