Problem:
Maximum Sum Sequence

Given a sequence of numbers a1, a2, a3, ..., an, find the maximum sum of a contiguous subsequence of those numbers. Note that, a subsequence of one element is also a contiquous subsequence.

Input

The input consists of multiple datasets. Each data set consists of:

n
a1
a2
.
.
an

You can assume that 1 ≤ n ≤ 5000 and -100000 ≤ ai ≤ 100000.

The input end with a line consisting of a single 0.

Output

For each dataset, print the maximum sum in a line.

Sample Input

7
-5
-1
6
4
9
-6
-7
13
1
2
3
2
-2
-1
1
2
3
2
1
-2
1
3
1000
-200
201
0

Output for the Sample Input

19
14
1001

Solution in Python (judge verdict: Wrong Answer)

while 1:
    n=input()
    if n==0:break
    a=[int(raw_input()) for _ in xrange(n)]
    wa=[0]*(n+1)
    max_a=-1000000
    for i in xrange(n):
        wa[i+1]=a[i]+wa[i]
    for i in xrange(n):
        for j in xrange(i,n+1):
            if max_a<wa[j]-wa[i]:
                max_a=wa[j]-wa[i]
    print(max_a)