Sugar Cane Farm Autoclock

a=1

while true do
  print(a)
  if a >= 60 then
    print("Activating pistons...")
    redstone.setOutput("back", true)
    sleep(2)
    print("Deactivating pistons")
    redstone.setOutput("back", false)
    a=0
  end
  a = a+1
  sleep(1)
end