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 PHP7 (7.0.15) (judge verdict: Wrong Answer)

<?php
fscanf(STDIN,"%s", $s);
fscanf(STDIN,"%d", $k);

function solve($s, $k) {
    $s = str_split($s);
    $s_c = count($s);
    $c = 0;
    $f = true;
    for ($i=0; $i < $s_c; $i++) {
        if($s[0] !== $s[$i]) {
            $f = false;
        }
        if ($i - 1 >= 0 && $s[$i - 1] === $s[$i]) {
            $s[$i] = '*';
            $c++;
        }
    }
    if($f) return floor($s_c * $k / 2);
    $c *= $k;
    if($s[0] === $s[$s_c - 1]) {
        for ($i=0; $i < $s_c; $i++) {
            if ($s[$i] !== $s[0]) {
                if($i % 2 !== 0) {
                    $c += $k - 1;
                }
                break;
            }
        }
    }
    return $c;
}
echo solve($s, $k);
?>