Count how many substrings start and end with the same character (simple logic).

Difficulty: Hard

Phase: 5 · Strings

XP Reward: 30 XP

Topics: Strings, Hard

Supported Languages: Python, JavaScript, C, C++, Java

Problem Description

Count how many non-empty substrings begin and end with the exact same character. Input Format: Read input from standard input (stdin). Output Format: Print the result to standard output (stdout).

Constraints

-10^9 <= N <= 10^9

Examples

Example 1

Input: aba

Output: 4

Explanation: Sample execution for input aba