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 Kotlin (1.0.0) (judge verdict: Wrong Answer)

fun main(args: Array<String>) {
    agc039a()
}

fun agc039a() {
    val s = readLine()!!
    val k = readLine()!!.toLong()

    var beforeChar: Char? = null
    val charCount = mutableListOf<Long>()
    for (i in s.indices) {
        if (beforeChar != null && s[i] == beforeChar) {
            val last = charCount[charCount.lastIndex]
            charCount.removeAt(charCount.lastIndex)
            charCount.add(last)
        } else {
            charCount.add(1L)
        }
        beforeChar = s[i]
    }

    val inside = charCount.map { it / 2 }.sum()

    val between = if (s.length > 1 && s.first() == s.last() && s[s.lastIndex] != s[s.lastIndex - 1]) 1 else 0

    val answer = inside * k + between * (k - 1)

    println(answer)
}