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.*;
import java.lang.*;
public class Main{
public static void main(String[] args) throws FileNotFoundException, IOException{
       Scanner s=new Scanner(System.in);
      String ss=s.nextLine();
      int i=0,j=ss.length()-1;
      int re=0;
      while(i<j){
      	if(ss.charAt(i)!=ss.charAt(j)){re++;}
      	i++;j--;
      }
      System.out.println(re);
      	
      }
        }