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 C (GCC 5.4.1) (judge verdict: Accepted)

#include<stdio.h>

int main() {

    long cnt['z'+1]={};
    while( (cnt[1]=getchar())<='z' && cnt[1]>='a' ){
        cnt[0]++; cnt[cnt[1]]++;
    }
    cnt[0] = cnt[0]*(cnt[0]-1)/2;
    for( int i = 'a'; i < 'z'+1; i++){
        cnt[0] -= cnt[i]*(cnt[i]-1)/2;
    }
    printf ("%lld\n", cnt[0]+1 );

    return 0;
}