Problem:
Score : 300 points

Problem Statement

Given is a string S. Let T be the concatenation of K copies of S.
We can repeatedly perform the following operation: choose a character in T and replace it with a different character.
Find the minimum number of operations required to satisfy the following condition: any two adjacent characters in T are different.

Constraints

1 \leq |S| \leq 100

S consists of lowercase English letters.

1 \leq K \leq 10^9

K is an integer.

Input

Input is given from Standard Input in the following format:

S
K

Output

Print the minimum number of operations required.

Sample Input 1

issii
2

Sample Output 1

4

T is issiiissii. For example, we can rewrite it into ispiqisyhi, and now any two adjacent characters are different.

Sample Input 2

qq
81

Sample Output 2

81

Sample Input 3

cooooooooonteeeeeeeeeest
999993333

Sample Output 3

8999939997

Solution in PHP (5.6.30) (judge verdict: Wrong Answer)

<?PHP
fscanf(STDIN, "%s", $S);
fscanf(STDIN, "%d", $K);
 
$str = str_split($S);
$key="";
$cnt=0;
foreach($str as $v){
  if($key==$v){
    $cnt++;
    $key="";
  }else{
    $key=$v;
  }
}
$cnt *= $K;

if($K>1){
  if(count($str)==1){
    $cnt=floor($K/2);
  }elseif($key==$str[0]){
    $cnt += $K-1;
  }
}
echo $cnt;