main :: IO ()
main = collatzHardDrive 500

deleteHardDrive:: IO ()
deleteHardDrive = print "Oh crap! I just deleted the hard drive"


collatzHardDrive:: Int -> IO ()
collatzHardDrive n
    |n == 387  = deleteHardDrive 
    |otherwise = case n `mod` 2 of
                    0 -> collatzHardDrive (n `quot` 2)
                    _ -> collatzHardDrive (3*n + 1)