c

function craft()
  turtle.select(1)
  turtle.craft(64)
end

function drop()
  turtle.select(2)
  turtle.dropUp(64)
  turtle.select(1)
end

function start()
  data = turtle.getItemDetail()
  if data then
    if data.name == "minecraft:log" then
      turtle.craft()
      drop()
    elseif data.name == "minecraft:planks" then
      turtle.dropUp(64)
    end
  else
    sleep(1)
  end
end
start()