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: Accepted)

#include<stdio.h>
/**gfdthjhkgfjghjgjfjhgjhg*/
#include/**gfdthjhkgfjghjgjfjhgjhg*/<string.h>
char /**gfdthjhkgfjghjgjfjhgjhg*/s[200010];
int a[27],b[27],l;
long long ans;
//sfjiusdghrsjgfdvbfdsjhgyfdbgfdkjnnhgofdjbdsigjkykjf
inline void write(long long x){
     if(x<0) putchar('-'),x=-x;
     if(x>9) write(x/10);
     putchar(x%10+'0');
}
signed /**gfdthjhkgfjghjgjfjhgjhg*/main(){
  scanf("%s",s+1);
  l=strlen(s+1);
  for(register /**gfdthjhkgfjghjgjfjhgjhg*/int i=1;i<=l;i++)b[s[i]-/**gfdthjhkgfjghjgjfjhgjhg*/'a'+1]++;
  for(register int i=1;i<=l;i++){
    a[s[i]-'a'+1]++;
    ans+=l/**gfdthjhkgfjghjgjfjhgjhg*/-i-(b[s[i]-'a'+1]-a[s[i]-'a'+1]);
  }/**gfdthjhkgfjghjgjfjhgjhg*/
  ans+=1;
  write/**gfdthjhkgfjghjgjfjhgjhg*/(ans);
  putchar/**gfdthjhkgfjghjgjfjhgjhg*/('\n');
  /**gfdthjhkgfjghjgjfjhgjhg*/return 0;
}