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 Haskell (GHC 8.8.3) (judge verdict: Wrong Answer)

import qualified Data.ByteString.Char8 as BS
import Data.Maybe

readInt = fromIntegral . fst . fromJust . BS.readInteger

readString = map BS.unpack . BS.words

getInt = readInt <$> BS.getLine

getString = readString <$> BS.getLine

calc :: String -> Char -> Int -> Int
calc [] c k = 0
calc [c'] c k
  | c == c' = k - 1
  | otherwise = 0
calc s c k
  | c' == c'' = k + calc s'' c k
  | otherwise = calc s' c k
  where
    c' = head s
    s' = tail s
    c'' = head s'
    s'' = tail s'

main = do
  [s] <- getString
  k <- getInt
  print $ calc s (head s) k