Problem:
Score : 500 points

Problem Statement

You have a string A = A_1 A_2 ... A_n consisting of lowercase English letters.

You can choose any two indices i and j such that 1 \leq i \leq j \leq n and reverse substring A_i A_{i+1} ... A_j.

You can perform this operation at most once.

How many different strings can you obtain?

Constraints

1 \leq |A| \leq 200,000

A consists of lowercase English letters.

Input

Input is given from Standard Input in the following format:

A

Output

Print the number of different strings you can obtain by reversing any substring in A at most once.

Sample Input 1

aatt

Sample Output 1

5

You can obtain aatt (don't do anything), atat (reverse A[2..3]), atta (reverse A[2..4]), ttaa (reverse A[1..4]) and taat (reverse A[1..3]).

Sample Input 2

xxxxxxxxxx

Sample Output 2

1

Whatever substring you reverse, you'll always get xxxxxxxxxx.

Sample Input 3

abracadabra

Sample Output 3

44

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.*;

public class Main {

    static public void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        char[] chs = sc.next().toCharArray();
        long n = chs.length;

        Map<Character, Long> countMap = new HashMap<>();

        for(char ch: chs) {
            if(!countMap.containsKey(ch)) {
                countMap.put(ch, 1L);
            } else {
                countMap.computeIfPresent(ch, (c, l) -> l + 1);
            }
        }

        long count = n * (n - 1) / 2 + 1;
        for(char ch: countMap.keySet()) {
            long m = countMap.get(ch);
            count -= m * (m - 1) / 2;
        }

        System.out.println(count);
    }
}