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 JavaScript (node.js v5.12) (judge verdict: Runtime Error)

// Java Implementation of the above approach  
import java.util.*; 
  
class GFG 
{ 
  
// Function to find the minimum number  
// character change required  
static void change(String s) 
{ 
  
    // Finding the length of the string  
    int n = s.length();  
  
    // To store the number of replacement operations  
    int cc = 0; 
  
    for(int i = 0; i < n/2; i++) 
    { 
  
        // If the characters at location  
        // i and n-i-1 are same then  
        // no change is required  
        if(s.charAt(i) == s.charAt(n - i - 1))  
            continue; 
  
        // Counting one change operation  
        cc += 1; 
  
        // Changing the character with higher  
        // ascii value with lower ascii value  
        if(s.charAt(i) < s.charAt(n - i - 1))  
            s = s.replace(s.charAt(n - i - 1),s.charAt(i)); 
        else
            s = s.replace(s.charAt(n),s.charAt(n - i - 1)); 
    } 
    System.out.println("Minimum characters to be replaced = "+(cc)) ; 
    System.out.println(s);  
}