Given a string s, return the number of palindromic substrings in it.
A string is a palindrome when it reads the same backwards as forward. A substring is a contiguous sequence of characters within the string.
Input: s = "abc" Output: 3 Explanation: The palindromic substrings are "a", "b", and "c" (each single character is a palindrome).
Input: s = "aaa" Output: 6 Explanation: The palindromic substrings are "a" (x3), "aa" (x2), and "aaa" (x1), for a total of 6.
s consists of lowercase English letterss = "abc"