import Data.Char (isDigit)

parse :: [String] -> [Int]
parse xs =
  let splitOps [] = []
      splitOps os = case span isDigit os of
        (op, _ : rest) -> read op : splitOps rest
        (op, _) -> [read op]
      ops = splitOps (dropWhile (not . isDigit) $ last xs)
   in ops

disassemble :: [Int] -> [String]
disassemble (opcode : operand : xs) =
  let combo :: Int -> String
      combo 4 = "A"
      combo 5 = "B"
      combo 6 = "C"
      combo op | op >= 7 = "invalid opcode " ++ show op
      combo op = show op
   in ( case opcode of
          0 -> "A <- A >> " ++ combo operand
          1 -> "B <- B xor " ++ show operand
          2 -> "B <- " ++ combo operand ++ " mod 8"
          3 -> "IF A != 0 THEN JMP " ++ show operand -- jnz
          4 -> "B <- B xor C"
          5 -> "OUT <- " ++ combo operand ++ " mod 8"
          6 -> "B <- A >> " ++ combo operand
          7 -> "C <- A >> " ++ combo operand
          x -> error $ "invalid opcode " ++ show x
      )
        : disassemble xs
disassemble _ = []

main :: IO ()
main = interact $ unlines . disassemble . parse . lines