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 Ruby (2.3.3) (judge verdict: Wrong Answer)

S=gets.chomp
K=gets.chomp.to_i

if S.size == 1
  puts K/2
else
  have_to_change_count = S.scan(/(.)\1+?/).size
  if S[0] == S[-1] &&
    S.scan(/^#{S[0]}+/).first&.size.odd? &&
    S.reverse.scan(/^#{S[-1]}+/).first.size.odd?

    puts ((have_to_change_count + 1) * K - 1)
  else
    puts (have_to_change_count * K)
  end
end