print("Seconds on?")
on=tonumber(read())
print("Seconds off?")
off=tonumber(read())
while true do
    redstone.setOutput("front", true)
    redstone.setOutput("top", true)
    os.sleep(on)
    redstone.setOutput("front", false)
    redstone.setOutput("top", false)
    os.sleep(off)
end