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: Accepted)

using System;

class A
{
	static void Main()
	{
		var s = Console.ReadLine();
		var k = long.Parse(Console.ReadLine());

		var sum = 0;
		var c = s[0];
		for (int i = 1; i < s.Length; i++)
		{
			if (c == s[i]) { sum++; c = '!'; }
			else c = s[i];
		}

		if (s[0] != s[s.Length - 1])
		{
			Console.WriteLine(k * sum);
		}
		else
		{
			var t1 = s.Length - s.TrimStart(s[0]).Length;
			if (t1 == s.Length)
			{
				Console.WriteLine(k * t1 / 2);
			}
			else
			{
				var t2 = s.Length - s.TrimEnd(s[0]).Length;
				Console.WriteLine(k * sum + (t1 % 2 == 1 && t2 % 2 == 1 ? k - 1 : 0));
			}
		}
	}
}