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)

def sum(a,i,j)
  sum = 0
  for k in i..j
    sum = sum + a[k]
  end
  sum
end

while true
  n = gets.to_i
  if n == 0
    break
  end
  a = Array.new(n)
  for i in 0..n-1
    a[i] = gets.to_i
  end
  max = 0
  for i in 0..n-1
    for j in i..n-1
      max = [max,sum(a,i,j)].max
    end
  end
  puts max
end