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)

import java.util.*

fun main(args: Array<String>) {
    val scanner = Scanner(System.`in`)
    val s = scanner.next()
    val k = scanner.nextLong()
    var prev = s[0]
    var check = true
    var check2 = false
    var dCount = 0
    var sum = 0
    for(c in s){
        if(check) {
            check = false
            continue
        }
        if(c == prev) dCount++
        else {
            sum += (dCount+1) / 2
            dCount = 0
        }
        prev = c
        //println(dCount)
    }
    if(dCount != 0){
        sum += (dCount+1) / 2
    }
    //println("${s[0]}=${s[s.length-1]}")
    if(s[0] == s[s.length-1]){
        if(dCount == 0) {
            sum++
            check2 = true
        }
        else if(dCount != 0 && dCount % 2 == 0) {
            sum++
            check2 = true
        }
    }
    if(check2) println(sum * k - 1L)
    else println(sum * k)
}