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 Lua (5.3.2) (judge verdict: Accepted)

local s = io.read()
local n = #s
local t = {}
for i = 1, 26 do
  t[i] = 0
end
do
  local a = s:sub(1, 1):byte() - 96
  t[a] = t[a] + 1
end
local ret = 1
for i = 2, n do
  local a = s:sub(i, i):byte() - 96
  ret = ret + i - 1 - t[a]
  t[a] = t[a] + 1
end
print(ret)