You are given a string S, the task is to reverse the string using stack.

Example 1:

Input: S="GeeksforGeeks"
Output: skeeGrofskeeG

Your Task:
You don't need to read input or print anything. Your task is to complete the function reverse() which takes the string S as an input parameter and returns the reversed string.

Expected Time Complexity: O(N)
Expected Auxiliary Space: O(N)

Constraints:
1 ≤ length of the string ≤ 100