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>) {
    val S = readInputLine().toCharArray()
    val K = readInputLine().toLong()

    var allSame = true

    for (i in 1 until S.size) {
        if (S[i] != S[i - 1]) {
            allSame = false
            break
        }
    }
    if (allSame) {
        println(S.size * K / 2L)
        return
    }

    var concurrentCnt = 0L

    for (i in 1 until S.size) {
        if (S[i] == S[i - 1]) {
            concurrentCnt++
            S[i] = '*'
        }
    }

    if (S[S.size - 1] == S[0]) {
        var header = 1L
        for (i in 1 until S.size) {
            if (S[i] == S[i - 1]) {
                header++
            } else {
                break
            }
        }
        var footer = 1L
        for (i in S.size - 2 downTo 0) {
            if (S[i] == S[i + 1]) {
                footer++
            } else {
                break
            }
        }

        println(concurrentCnt * K - (K - 1) * (header / 2L + footer / 2L - (header + footer) / 2L))
    } else {
        println(concurrentCnt * K)
    }
}

fun readInputLine(): String {
    return readLine()!!
}