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: Accepted)

/*
ID: toooooEasy or RafaelSaddatimov
PROG:
*/
#include <bits/stdc++.h>
#define MAX 3009
#define MOD 1000000007
#define INF 2100000000
#define EPS 1e-12
#define ll long long
#define _l long
#define F first
#define S second
#define NLINE printf("\n")
#define BYE(v) return 0 * printf(v)
#define all(v) v.begin(), v.end()
#define pb push_back
using namespace std;
ll c[26];

int main()
{
    string s;
    cin >> s;
    ll n = (ll)s.size();
    ll tot = n * (n - 1) / 2;
    for(int i=0; i<s.size(); ++i)
        c[s[i]-'a']++;
    for(ll i=0; i<26; ++i)
        if(c[i] > 1)
            tot = tot - c[i] * (c[i] - 1) / 2;
    printf("%lld", tot + 1);
}