[LUA] Can't figure out what's wrong with this function

-- START VARIABLES --
local width = 0
local length = 0
local totalblocks = 0
local fuellevel = 0
local xpos = 0
local ypos = 0
local invslot
-- END VARIABLES --
-- START FUNCTIONS --
function checkInv()
  turtle.select(1)
  local count = 0
  for i = 1, 16 do
	turtle.select(i)
	count = count + turtle.getItemCount()
  end
  if count >= totalblocks then
	return true
  else
	return false
  end
end
function placeX(width)
  if turtle.detect() then
	turtle.dig()
	turtle.forward()
	xpos = xpos + 1
	turtle.placeDown()
  end
end
-- END FUNCTIONS --
print("Welcome to the pad builder!")
print("---------------------------")
print("How wide should the pad be?")
width = io.read()
print("Width " .. width)
print("How long should the pad be?")
length = io.read()
print("Width " .. width)
print("Length " .. length)
totalblocks = width * length
print("You need " .. totalblocks .. " blocks to accomplish this.")
fuellevel = turtle.getFuelLevel()
print("You have " .. fuellevel .. " fuel.")
print("You need " .. totalblocks .. " fuel.")
if fuellevel < totalblocks then
  print("Not enough fuel to perform this action.  Exiting.")
  sleep(5)
  shell.exit()
end
if not checkInv() then
print("Not enough blocks")
end