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 Python (3.4.3) (judge verdict: Time Limit Exceeded)

def main():
     count = 1
     s = list(input())
     for i in range(1,len(s)):
         for j in range(0,len(s)-i):
             flag = check(s[j:j+i+1])
             if not flag:
                 count+=1
     print(count)

def check(s):
    i = 0
    while i <(len(s)>>1):
        if s[i]!=s[-i-1]:
            return False
        return True

if __name__=="__main__":
    main()