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)

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<algorithm>
#include<vector>
#include<queue>
using namespace std;
int main(void){
	char a[200010];
	long long b[100];
	int c, d;
	int k;
	int n, m;
	int s, t;
	long long w, x, y, z;
	long long ans;
	for (int i = 0; i < 200010; i++)a[i] = 0;
	for (int i = 0; i < 100; i++)b[i] = 0;
	scanf("%s", a);
	x = strlen(a);
	for (int i = 0; i < x; i++){
		b[a[i] - 97]++;
	}
	ans = x*(x - 1);
	ans = ans / 2;
	for (int i = 0; i < 26; i++){
		y = b[i] * (b[i] - 1);
		y = y / 2;
		ans = ans - y;
	}
	ans++;
	printf("%lld\n", ans);


	return 0;

}