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 Ruby (judge verdict: Accepted)

while (line = gets)
  n = line.chop.to_i
  if (n == 0)
    break
  end

  max = nil
  subseq = Array.new

  n.times do
    a = gets.chop.to_i

    for i in (0...subseq.length)
      subseq[i] += a
    end
    subseq.push a

    cmax = subseq.max

    if (max.nil? || max < cmax)
      max = cmax
    end
  end

  puts max
end