Given a string S, check if it is palindrome or not.

Example 1:

Input: S = "abba"
Output: 1
Explanation: S is a palindrome

Example 2:

Input: S = "abc" 
Output: 0
Explanation: S is not a palindrome

Your Task:  
You don't need to read input or print anything. Complete the function isPlaindrome() which accepts string S and returns a boolean value

Expected Time Complexity: O(Length of S) 
Expected Auxiliary Space: O(1) 

Constraints:
1 <= Length of S <= 10⁵