Dynamic Array Operations

This problem requires you to implement a dynamic array that supports several operations. You are to design a data structure for a dynamic array of integers that supports the following operations efficiently:

• append x: Append an integer x to the end of the array.
• remove i: Remove the integer at index i (0-indexed).
• get i: Get and output the integer at index i.
• sum: Compute and output the sum of all integers in the array.

Initially, the array is empty. The operations will be provided sequentially. For every get or sum operation, output the result on a separate line.

Example:

Input:
7
append 1
append 2
append 3
get 1
remove 1
get 1
sum
Output:
2
3
4

</p>

inputFormat

The first line contains an integer T representing the number of operations. The following T lines each contain an operation in one of the following formats:

• append x — where x is an integer to append.
• remove i — where i is a 0-indexed position to remove.
• get i — where i is the index whose value is to be printed.
• sum — which requires printing the sum of all integers in the array.

outputFormat

For every get and sum operation in the input, print the corresponding result on a new line.

## sample

7
append 1
append 2
append 3
get 1
remove 1
get 1
sum

2
3
4

</p>