import Control.Monad
import System.IO

normalize = reverse . take 3 . reverse . ("00" ++)

main = main' (map (normalize . show) [0..999])
 where
  main' [] = mzero
  main' (p:ps) = do
   putStrLn p
   ack <- getLine
   hFlush stdout
   guard (ack == "unlocked")
   main' ps