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.Scanner;
class Main
{
    static boolean isPalindrome(char []str)
    {
        int len = str.length;
        if (len == 1)
            return true;
        char ptr1 = str[0];
        char ptr2 = str[len-1];
        while (ptr2 >= ptr1)
        {
            if (ptr1 != ptr2)
                return false;
            ptr1++;
            ptr2--;
        }
        return true;
    }
    static int noOfAppends(String s)
    {
        if (isPalindrome(s.toCharArray()))
            return 0;
        s = s.substring(1);
        return 1 + noOfAppends(s);
    }
    public static void main(String arr[])
    {
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        System.out.printf("%d\n", noOfAppends(s));
    }
}