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)

class Maximum
  def initialize
    @result = []
 
    while(@n = $stdin.gets.chomp.to_i)
      @max = -1000000
      if @n != 0
        calc  
      else
        break
      end
    end
    render
  end
 
  def calc
    sum = 0
    @n.times do
      val = $stdin.gets.chomp.to_i
      if val < 0
        sum += val
        if @max < sum
          @max = sum
        end
        if sum <= 0
          sum = 0
        end
      else
        sum += val
        if @max < sum
          @max = sum
        end
      end
    end
    @result.push(@max)
  end
 
  def render
    @result.each do |val|
      puts val
    end
  end
end
 
m = Maximum.new