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

namespace AtCoder_20190707_1
{
    class Program
    {
        static void Main(string[] args)
        {
            char[] s = Console.ReadLine().ToCharArray();
            int k = int.Parse(Console.ReadLine());

            int count = 0;

            for(int i = 1; i < s.Length; i++)
            {
                if(s[i - 1] == s[i])
                {
                    count++;
                    s[i] = 'A';
                }
            }

            if(s[0] == s[s.Length - 1])
            {
                Console.WriteLine(count * k + k - 1);
            }
            else
            {
                Console.WriteLine(count * k);
            }
        }
    }
}