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)

# coding: utf-8

class Max
  def solve
    loop do
      n = gets.chomp.to_i
      break if n == 0

      max = -10000
      sum = 0
      n.times do
        a = gets.chomp.to_i
        sum += a
        if a < 0 then
          if sum < 0 then
            sum = 0
          end
        else
          if max < sum
            max = sum
          end
        end
      end
      puts max
    end
  end
end

Max.new.solve