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++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <iostream>
#include <cstring>
using namespace std;
char s[200003];
int n,nr[200];
long long sol;
int main()
{
    cin.getline(s+1,200003);
    n=strlen(s+1);
    for(int i=1;i<=n;++i) ++nr[s[i]];
    for(int i='a';i<'z';++i)
    {
        for(int j=i+1;j<='z';++j) sol+=nr[i]*nr[j];
    }
    //long long usu=n*(n-1)/2;
    //usu=usu-sol;
    cout<<sol+1;
    return 0;
}