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 Python (3.4.3) (judge verdict: Wrong Answer)

# Python 3 program for getting minimum character 
# to be added at front to make string palindrome 

# function for checking string is 
# palindrome or not 
def ispalindrome(s): 

	l = len(s) 
	
	i = 0
	j = l - 1
	while i <= j: 
	
		if(s[i] != s[j]): 
			return False
		i += 1
		j -= 1
	
	return True

# Driver code 
if __name__ == "__main__": 
	
	s = "BABABAA"
	cnt = 0
	flag = 0
	
	while(len(s) > 0): 
	
		# if string becomes palindrome then break 
		if(ispalindrome(s)): 
			flag = 1
			break
		
		else: 
			cnt += 1
		
			# erase the last element of the string 
			s = s[:-1] 
	
	# print the number of insertion at front 
	if(flag): 
		print(cnt) 

# This code is contributed by ita_c