wood

a = {...}
d = a[1]

function place()
  local s = 1
  for i = 1,16 do
    if turtle.getItemCount(i) > 0 then
      s = i
      break
    end
  end
  turtle.select(s)
  turtle.placeDown()
end

for i=0,d do
  turtle.forward()
  place()
end