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: Time Limit Exceeded)

loop do
   n=gets.to_i
   break if n==0
   arr=[]
   n.times do
      arr << gets.to_i
   end 
   result=[]
   0.upto(n-1) do |i|
      next if i!=0 and arr[i]<arr[i-1] 
      i.upto(n-1) do |j|
         buf=arr[i..j].inject(:+)
         result << buf
         min=buf if min.nil?
         if !result.empty? and buf < min then
            min=buf
            break
         end
      end
   end
   puts result.max
end