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 <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <iostream>
#include <algorithm>
#include <queue>
#include <map>
#include <stack>
using namespace std;
const int MAXN = 2e6 + 5;
char s[MAXN];
int a[MAXN];
int vis[50];
int main()
{
    scanf("%s",s+1);
    int n = strlen(s+1);
    int t = 0,ans = 0;
    for(int i = 1; i <= n; i++) vis[s[i]]++;
    for(int i = 'a'; i <= 'z'; i++){
        for(int j = i + 1; j <= 'z'; j++){
            ans += vis[i] * vis[j];
        }
    }
    printf("%d\n",ans+1);
}