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: Time Limit Exceeded)

#include<set>
#include<map>
#include<stack>
#include<queue>
#include<deque>
#include<cstdio>
#include<string>
#include<vector>
#include<math.h>
#include<time.h>
#include<utility>
#include<cstdlib>
#include<sstream>
#include<cstring>
#include<stdio.h>
#include<iomanip>
#include<iostream>
#include<algorithm>
//#include<conio.h>
//ios::sync_with_stdio(false);
using namespace std;
string str;
vector<string> ve;
int main(){
	cin>>str;
	for(int i=0;i<str.size()-1;i++){
		string tmp1,tmp2,tmp3;
		tmp2+=str[i];
		for(int k=0;k<i;k++) tmp1+=str[k];
		for(int j=i+1;j<str.size();j++){
	        tmp2+=str[j];
	        string retmp=tmp2;
	        reverse(retmp.begin(),retmp.end());
	        if(retmp==tmp2) continue;
	        tmp3.clear();
	        for(int k=j+1;k<str.size();k++) tmp3+=str[k];
	        ve.push_back(tmp1+retmp+tmp3);
		}
	}
	sort(ve.begin(),ve.end());
	ve.erase(unique(ve.begin(),ve.end()),ve.end());
	cout<<ve.size()+1<<endl;
//	for(int i=0;i<ve.size();i++) cout<<ve[i]<<endl;
	return 0;
}