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**Task** | Statistics

Time limit: | 1.00 s | Memory limit: | 512 MB |

There is an array that consists of $n$ integers. Some values of the array will be updated, and after each update, your task is to report the maximum subarray sum in the array.

The first input line contains integers $n$ and $m$: the size of the array and the number of updates. The array is indexed $1,2,\ldots,n$.

The next line has $n$ integers: $x_1,x_2,\ldots,x_n$: the initial contents of the array.

Then there are $m$ lines that describe the changes. Each line has two integers $k$ and $x$: the value at position $k$ becomes $x$.

After each update, print the maximum subarray sum. Empty subarrays (with sum $0$) are allowed.

- $1 \le n, m \le 2 \cdot 10^5$

- $-10^9 \le x_i \le 10^9$

- $1 \le k \le n$

- $-10^9 \le x \le 10^9$

Input:

`5 3`

1 2 -3 5 -1

2 6

3 1

2 -2

Output:

`9`

13

6