startup

while true do
    os.pullEvent("redstone")
   while rs.getInput("left") do
      if redstone.getAnalogInput("front") < 3 then
    print(redstone.getAnalogInput("front"))
          redstone.setAnalogOutput("back", 2)
            sleep(25)
            redstone.setAnalogOutput("back", 0)
        end
    end
end