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.Generic;

namespace ConsoleApp1 {
    public class Class1 {
        static void Main(string[] args) {
            var S = Console.ReadLine();
            var K = long.Parse(Console.ReadLine());

            long s1 = 0;
            long s2 = 0;

            for (var i = 0; i < S.Length; i++) {
                if (i == S.Length - 1)
                    break;
                if (S[i] == S[i + 1]) {
                    s1++;
                    i++;
                }
            }
            S += S;
            for (var i = 0;i < S.Length; i++) {
                if (i == S.Length - 1)
                    break;
                if (S[i] == S[i + 1]) {
                    s2++;
                    i++;
                }
            }
            Console.Write(s1 * (K % 2) + s2 * (K / 2));
        }
    }
}