Inproved Door Pass

while true do
 term.clear()
 term.setCursorPos(1, 1)
 print("Please Enter Password:")
 input = read("*")
 if input == "door" then
  redstone.setOutput("back", true)
  sleep(2)
  redstone.setOutput("back", false)
  end
  elseif input == "shell" then
  shell.exit()
  end
  else
  print("Access Denied.")
 end
end