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 Fortran (GNU Fortran 9.2.1) (judge verdict: Accepted)

program main
    use,intrinsic :: iso_fortran_env
    implicit none
    character(200000):: a
    integer(int64):: i,l,ia,ans
    integer(int64):: cnt(ichar("a"):ichar("z"))
    
    read*, a
    cnt(:) = 0
    l = len_trim(a)
    do i=1,l
        ia = ichar(a(i:i))
        cnt(ia) = cnt(ia) + 1
    end do

    ans = (l*(l-1))/2
    do i=ichar("a"),ichar("z")
        ans=ans-(cnt(i)*(cnt(i)-1))/2
    end do
    print'(i0)', ans+1
end program main