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.io.*;

public class Main{
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s = sc.nextLine();
		int n = s.length();
		int lm = 0;
		if(n % 2 == 0){
			lm = n/2;
		}else{
			lm = n/2;
		}
		//System.out.println(lm);
		int i = 0, j = n - 1;
		int count = 0;
		while(i < lm ){
			//System.out.println(s.charAt(i));
			if(s.charAt(i) != s.charAt(j)){
				count++;
			}
			i++;
			j--;
		}
		System.out.println(count);
		
	}
		
		
}