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: Wrong Answer)

import java.util.*;
public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    String data = sc.nextLine();
    String dataR = "";
    int notCount = 0;
    for (int i = data.length()-1 ; i >= 0 ; i--) {
      dataR += data.substring(i,i+1);
    }
    for (int i = 0 ; i < data.length() ; i++) {
      if (!data.substring(i,i+1).equals(dataR.substring(i,i+1))) {
        notCount++;
      }
    }
    
    System.out.println(notCount);
    
  }
}