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 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>
#include <string.h>

int fountain(int x1, int y1, int x2, int y2, int y[]);

int main(void) {
	char a[200010];
	int l;
	long long int ans = 1;
	scanf("%s", a);
	l = strlen(a);

	for (int i = 2; i <= l; i++)
	{
		for (int j = 0; j <= l - i; j++)
		{
			int k;
			for (k = 0; k < i/2; k++)
			{
				if (a[j + k] != a[j + i - k - 1]) {
					ans++;
					break;
				}
			}
		}
	}

	printf("%d", ans);

	return 0;
}