Problem:
Score : 200 points

Problem Statement

Takahashi loves palindromes. Non-palindromic strings are unacceptable to him. Each time he hugs a string, he can change one of its characters to any character of his choice.

Given is a string S. Find the minimum number of hugs needed to make S palindromic.

Constraints

S is a string consisting of lowercase English letters.

The length of S is between 1 and 100 (inclusive).

Input

Input is given from Standard Input in the following format:

S

Output

Print the minimum number of hugs needed to make S palindromic.

Sample Input 1

redcoder

Sample Output 1

1

For example, we can change the fourth character to o and get a palindrome redooder.

Sample Input 2

vvvvvv

Sample Output 2

0

We might need no hugs at all.

Sample Input 3

abcdabc

Sample Output 3

2

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.*;
import java.util.Collections;

public class Main{
    public static void main(String[] args){
 
        Scanner sc = new Scanner(System.in);
        String a = sc.next();
        int n = a.length();
      int b = 0;
        
      
        if(n%2==0){
          for(int i = 0; i < n/2; i++){
            
            char c1 = a.charAt(i);
            char c2 = a.charAt(n-1-i);
            if(c1 != c2){
              b++;
          
            }
          }
          
          
          
          System.out.println(b);
        
        } else {
          for(int i = 0; i < (n-1)/2; i++){
            
            char c1 = a.charAt(i);
            char c2 = a.charAt(n-1-i);
            if(c1 != c2){
              b++;
          
            }
          }
          System.out.println(b);
        } 
      
      
    }
}