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 <bits/stdc++.h>

#define INF 0x3f3f3f3f
#define NINF -0x3f3f3f3f

using namespace std;

typedef pair<int,int> pii;

char str[200005];
int total[30];

int main ()
{
	scanf("%s",str);
	
	int len = strlen(str);
	
	long long ans = 1;
	for (int i = 0; i < len; i += 1)
	{
		int idx = str[i]-'a';
		
		int diff = i-total[idx];
		total[idx]++;
		
		ans += diff;
		
	}
	
	printf("%lld\n",ans);
	
	return 0;
}