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 Scala (2.11.7) (judge verdict: Accepted)

import java.util.Scanner

object Main {
  def main(args: Array[String]) {
    val result = solve(new Scanner(System.in))
    if (result.length > 0) println(result)
  }

  def solve(in: String): String = solve(new Scanner(in))

  def cnt(s: String): Long = {
    var cnt = 0L
    var prev = '.'
    s.foreach { c =>
      if (prev == c) {
        cnt += 1
        prev = '.'
      } else {
        prev = c
      }
    }
    cnt
  }

  def solve(sc: Scanner): String = {
    val S = sc.next
    val K = sc.nextInt

    val c1 = cnt(S)
    val c2 = cnt(S * 2) - c1
    val c3 = cnt(S * 3) - (c1 + c2)
    if (c1 == c3) {
      (((K / 2) * (c1 + c2)) + (K % 2) * c1).toString
    } else {
      (c1 + ((K - 1) * c2)).toString
    }
  }
}