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 C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<stdio.h>
# define BUFSIZE 100

int  main(void){
char hoge[BUFSIZE]=	{0};
int i=0;

scanf(" %s",&hoge);
	for(i=0;i<BUFSIZE;i++){
		if(hoge[i]=='\0'){
			break;
			}
		}
///debug

printf("%d",i);
/*
	printf(" %s",hoge);
	*/
	

int m=0;
	if(i%2==0){
		for(int j=0;j<=(i/2-1);j++){
				if(hoge[j]!=hoge[i-1-j]){
						m++;
					}
		}
	}else{
		for(int j=0;j<(i-1)/2;j++){
				if(hoge[j]!=hoge[i-1-j]){
						m++;
				}
		}
	}

printf(" %d",m);

}