Maximum Positive Revenue

You are given the revenue of a business for n consecutive days in an array where the i^th element represents the revenue for the i^th day. Your task is to compute the maximum positive revenue that can be obtained by considering any continuous subarray of days. Formally, you need to find

$$\max_{1\le i \le j \le n} \left(\sum_{k=i}^{j} a_k\right)$$

If no positive subarray exists, output 0.

Note: A subarray consists of a contiguous segment of the array.

inputFormat

The first line contains a single integer n that indicates the number of days.

If n > 0, the second line contains n space-separated integers representing the revenue for each day. If n = 0, the second line is omitted.

outputFormat

Output a single integer which is the maximum positive revenue over any continuous subarray of days. If no such subarray exists, output 0.

7
-3 -2 4 -1 -2 1 5

7