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 C# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
using System.Text;


class Program
{
    static void Main(string[] args)
    {
        // 入力
        var s = Console.ReadLine();
        var k = int.Parse(Console.ReadLine());
        //int[] n = Console.ReadLine().Split().Select(int.Parse).ToArray();

        long count = 0;
        char[] c = s.ToCharArray();
        for (int i = 1; i < c.Length; i++)
        {
            if (c[i] == c[i - 1])
            {
                c[i] = '?';
                count++;
            }
        }

        count = count * k;

        if (c[0] == c[c.Length - 1])
        {
            count += k - 1;
        }

        if (c.Length == 1)
        {
            count = (k-1)/2;
        }

        // 出力
        Console.WriteLine(count);
    }
}