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: Runtime Error)

import java.util.*

fun main(args: Array<String>) {
    val sc = Scanner(System.`in`)
    val s = sc.next()
    val k = sc.nextLong()
    println(problemagc039(s, k))
}

fun problemagc039(s: String, k: Long): Long {
    val sa = s.toCharArray()
    var lastFrag = 0
    for (i in 0 until sa.size) {
        if (i == sa.size - 1) {
            if (sa[0] == sa[i]) {
                if (sa[i] != sa[i - 1]) {
                    lastFrag = 1
                }
                sa[i] = 'x'
            }
        } else {
            if (i != 0 && sa[i] == sa[i + 1] && sa[i] != sa[i - 1]) {
                sa[i + 1] = 'x'
            }
        }
    }
//    debugLog(sa.toList())

    return sa.toList().count { it == 'x' }.toLong() * k - lastFrag
}