Maximum Continuous Subsequence Sum

Problem Description

Given a sequence of $K$ integers $N_1, N_2, \dots, N_K$, a "continuous subsequence" is defined as $N_i, N_{i+1}, \dots, N_j$, where $1 \le i \le j \le K$. The "maximum continuous subsequence sum" is the largest among the sums of all such continuous subsequences. For example, given the sequence $-2, 11, -4, 13, -5, -2$, the continuous subsequence $11, -4, 13$ has the maximum sum, which is $20$.

Write a program to compute the maximum continuous subsequence sum of a given integer sequence.

Input Format

The first line gives a positive integer $K\ (\le 10^5)$.

The second line gives the $K$ integers, separated by spaces.

Output Format

Output the maximum continuous subsequence sum on a single line (guaranteed to fit within the range of int).

If all integers in the sequence are negative, output $0$.

Sample Input

6
-2 11 -4 13 -5 -2

Sample Output

20