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 Go (1.6) (judge verdict: Wrong Answer)

package main
import(
  "fmt"
)

func main(){
  var s []string 
  var num, count int
  fmt.Scan(&s)
  count = 0
  num = len(s) / 2
  if len(s) % 2 == 0{
    num = len(s) / 2
  } else {
    num = (len(s) / 2) +1
  }
  for i:=0; i < num; i++{
    if s[i] != s[len(s)-i]{
      s[len(s)-i] = s[i]
      count++
    }
  }
  fmt.Printf("%d", count)
}