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)


require 'pp'

def gets_num
  $stdin.gets.chomp.to_i
end

loop do
  n = gets_num
  break if n == 0
  list = n.times.map {gets_num}
  max = 0
  result = list.reduce(0) {|accum, x|
    max = accum if (max < accum)
    if (x + accum < 0) then 0
    else x + accum end
  }
  max = result if result > max
  if result == 0 then
    puts list.reduce {|x, accm| accm > x ? accm : x}
  else
    puts max
  end
end