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 Ruby (2.3.3) (judge verdict: Time Limit Exceeded)

require 'set'

#lines = <<'EOS'
#abracadabra
#EOS

#lines = <<'EOS'
#xxxxxxxxbbbyyyyyyyy
#EOS

lines = $stdin.read
array = lines.split("\n")

A = array[0].to_s

strings = Set.new

cnt = 0
all = 0

for i in 0...A.length do
  for j in 0...A.length do
    string = A.dup

    if i!=j and string[i] != string[j]
      string[i], string[j] = string[j], string[i]
      cnt = cnt + 1
      #puts "#{string} => #{cnt}, #{all}"
    end
    all = all + 1
    strings.add(string)
  end
end

puts strings.size