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.*;
public class Main{
	public static void main(String[] args){
		Scanner sc=new Scanner(System.in);
		String s=sc.next();
		char[] pp=new char[s.length()/2];
		for(int i=0; i<s.length()/2; i++){
			pp[i]=s.charAt(i);
		}
		int count=0;
		for(int i=s.length()-1; i>(s.length()-1)/2; i--){
			if(pp[s.length()-1-i]!=s.charAt(i)){
				count++;
			}
		}
		System.out.println(count);
	}
}