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 Kotlin (1.0.0) (judge verdict: Time Limit Exceeded)

import java.util.*
object MainKt {
  @JvmStatic fun main(args:Array<String>) {
    val A=readLine()!!
    val len=A.length
    
    var str_set:MutableSet<String> = mutableSetOf(A)

    for(i in 0.until(len)) {
      for(j in i.until(len)) {
        val reversed_text=A.slice(0.until(i))+A.slice(j downTo i)+A.slice((j+1).until(A.length))
        assert(reversed_text.length==A.length)
        // println("i:${i},j:${j},${reversed_text}")
        str_set.add(reversed_text)
      }
    }
    // println()
    println(str_set.size)
  }
}