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)


require 'pp'

loop do
  prefix = [];
  suffix = [];
  ans = true;
  n = $stdin.gets.chomp.to_i
  break if n == 0
  n.times do
    line = $stdin.gets.chomp
    prefix.push(line[0]);
    suffix.push(line[-1]);
  end
  puts (prefix.sort == suffix.sort) ? "OK" : "NG"
end