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: Wrong Answer)

# python template for atcoder1
import sys
sys.setrecursionlimit(10**9)
input = sys.stdin.readline


def solve():
    S = input()[:-1]
    N = len(S)

    palindrome = 0
    for i in range(N-1):
        for j in range(i+2, N+1):
            if check(S[i:j]):
                #print("{} is pali".format(S[i:j]))
                palindrome += 1

    return N*(N-1)//2-palindrome+1


def check(S):
    '''
    ret True if S is palindrome
    '''
    return all(c == r for c, r in zip(S, reversed(S)))


print(solve())