Segment Tree Queries and Updates

You are given an array of n integers and m operations. The operations are of two types:

• Update: Change the value at a given index.
• Query: Calculate the sum of the elements in a given range.

The operations use 1-indexed positions. For the update operation the format is:

$$1\; index\; value$$

which means update the element at position index to value.
For the query operation the format is:

$$2\; left\; right$$

This asks for the sum of the array elements from left to right (both inclusive). To solve this efficiently, you are required to use a segment tree. The segment tree should support point updates and range sum queries.

Note that each query result should be printed on a new line in the order of the queries encountered.

inputFormat

The first line contains two integers n and m, representing the number of elements in the array and the total number of operations, respectively.

The second line contains n space-separated integers denoting the initial array.

Then follow m lines where each line represents an operation.

• If the line starts with 1, it will be in the format: 1 index value, which means update the element at position index to value.
• If the line starts with 2, it will be in the format: 2 left right, which means output the sum of the subarray from left to right (inclusive).

outputFormat

For every operation of type 2, output the sum of the elements in the specified range on a new line.

## sample

5 3
1 2 3 4 5
1 3 10
2 1 3
2 2 5

13
21

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