item = "gravel"
maxStack = 64
sendSide = 3
parent = 1930
retriever = 1929
counter = 1963

itemID = 0
sorter = peripheral.wrap("front")

rednet.open("right")

getID = function()
	rednet.send(parent, textutils.serialize({[1]=1, [2]=item}))
	ID, message = rednet.receive()
	if ID == parent then
		itemID = message + 0
	end
end

get = function(cnt, side)
	stacks = math.floor(cnt / maxStack)
	extra = cnt % maxStack
	for i=1,stacks do
		sorter.extract(1, itemID, side, maxStack)
	end
	sorter.extract(1, itemID, side, extra)

	rednet.send(counter, textutils.serialize({[1]=itemID, [2]=cnt*-1}))

start = function()
	getID()

	sorter.sort(sendSide)

	while true do
		ID, message = rednet.receive()
		get(message + 0, sendSide)
	end
end

start()