How to interact with process in haskell

I compiled the following program

-- Alice.hs
main = do
  putStrLn "Hello"
  l <- getLine
  putStrLn $ "you said " ++ l

I want to communicate with Alice in another program: Bob.hs. My failed attempt is:

-- Bob.hs
import System.IO (hGetLine, hPutStrLn)
import System.Process (runInteractiveProcess)
main = do
  (hin, hout, herr, ph) <- runInteractiveProcess "./Alice" [] Nothing Nothing
  hello <- hGetLine hout
  putStrLn hello
  hPutStrLn hin "something"
  reply <- hGetLine hout
  putStrLn reply

Bob gets stuck before Hello is printed.