[-1,                                 3,                                                                             -1,                                                 5]
 |                                     |cur_val=3                                                             | cur_val=-1
cur_sum（初始化 ）      cur_sum=-1 <0 (没有贡献）                                 | cur_sum=3>0 (有贡献）                                                                                                        
max_sum（初始化 ）    重新计算cur_sum,因此cur_sum=cur_val =3      | cur_sum=cur_sum+cur_val =3-1=2
                                       max_sum=max(max_sum,cur_sum)=3             |max_sum=max(max_sum,cur_sum)=max(3,2)=3

step 1                        step2                                                                    step3 .......



def maxsumlist(n,l):
    currsum=l[0]
    maxsum=l[0]
    for i in range(1,n):
        if currsum>0:
            currsum+=l[i]
        else:
            currsum=l[i]
        maxsum=max(currsum,maxsum)
    return(maxsum)

n=int(input())
list_a=[int(i) for i in input().strip("[]").split(" ")]#convert string of list to list
print(maxsumlist(n, list_a))