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.Arrays;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s=sc.next();
		//String t= sc.next();
		String buff= "";
		String[] buff1=new String[s.length()];
		String[] buff2=new String[s.length()];
		//double n = sc.nextInt()/1000.0;
		//int m = sc.nextInt();
		//int k = sc.nextInt();
		long count=0,flag=0;
		long count1=0,count2=0;
		int count3=0;
		int[] array = new int[3];
		/*array[0]=n-m;
		array[1]=n*m;
		array[2]=n+m;*/
		Arrays.sort(array);

		for(int i=0;i<s.length()/2;i++) {
			buff1[i]=s.substring(i,i+1);
		}
		for(int i=s.length();i>s.length()/2;i--) {
			buff2[count3]=s.substring(i-1,i);
			count3++;
		}
		for(int i=0;i<s.length()/2;i++) {
			if(!buff1[i].equals(buff2[i])) {
				count++;
			}
			//System.out.println(buff1[i]);
			//System.out.println(buff2[i]);
		}
		/*if(s.length()%2==0) {
			for(int i=0;i<s.length()/2;i++) {
				for(int j=s.length();j>s.length()/2;j--) {
					if(!s.substring(i,i+1).equals(s.substring(j-1,j)))count++;
				}
			}
			System.out.println(count);
		}else{
			for(int i=0;i<s.length()/2;i++) {
				for(int j=s.length();j>s.length()/2;j--) {
					if(!s.substring(i,i+1).equals(s.substring(j-1,j)))count++;
				}
			}
			System.out.println(count);
		}*/

		System.out.println(count);
	}
}