Password Change

Interview

Time limit2sMemory limit512 MB

Summary

Find the minimum letter changes so the first K characters equal the last K characters.

Level: Easy3 of 10
Topics: String, Implementation
Solved: No attempts yet

Problem

A web service introduced a new password rule, and Yeongseon wants to update her password to satisfy it.

The rule is a single condition. The first $K$ letters of the password must be the same as the last $K$ letters.

The length of the password stays the same, and the letter at any position may be replaced with another lowercase letter. Given Yeongseon's old password and $K$ , write a program that finds the minimum number of letters that must be changed to satisfy the new rule.

Input

The first line contains the old password. It consists of lowercase letters only, and its length is at most $50$ .

The second line contains a positive integer $K$ . $K$ is at most the length of the old password.

Output

Print the minimum number of letters that must be changed to satisfy the new rule.

Examples4

Example 1
Input
```
abcabc
3
```
Expected output
```
0
```
Example 2
Input
```
loool
3
```
Expected output
```
1
```
Example 3
Input
```
abcdefgh
8
```
Expected output
```
0
```
Example 4
Input
```
amavckdkz
7
```
Expected output
```
5
```