Maximum Subarray Sum

You are given an array of integers. Your task is to find the maximum subarray sum. In other words, you need to find a contiguous subsequence whose sum is the largest among all possible subsequences.

If the array contains only non-positive numbers (i.e. every element is less than or equal to 0), then the answer should be 0. This can be formally written as:

\[ \text{if } \forall x \in arr,\; x \le 0, \quad \text{then } answer = 0 \]

Otherwise, compute the maximum sum of any contiguous subarray. This is a classic problem that can be solved using Kadane's Algorithm.

inputFormat

The input is given via standard input and consists of two lines:

• The first line contains an integer n representing the number of elements in the array.
• The second line contains n space-separated integers representing the elements of the array.

outputFormat

Output the maximum subarray sum to standard output. If the array only contains non-positive numbers, output 0.

## sample

5
-1 -2 -3 -4 -5

0

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