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: Wrong Answer)

#main
arr = Array.new
until (n = gets) == "0\n"
  a = Array.new
  (n.to_i).times do
    a << gets.to_i
  end
  arr << a
end
arr.each do |i|
  mss = 0
  sum = 0
  0.upto(i.length - 1) do |j|
    break if i[j] >= 0
    if j == (i.length - 1)
      next i.sort[-1] 
    end
  end
  0.upto(i.length - 1) do |j|
    sum += i[j]
    sum = 0 if sum < 0
    mss = sum if mss < sum
  end
  puts mss
end