IF and ELSE problems, why?

So im trying to make a button which opens a door, then you click it again and it closes it. Im not great at scripting but this is my attempt. (NOTE: the door works shutting and closing with a ontouch script.) The problem is that it keeps saying that error at the bottom. Ive tried lots of ends and it still says it.

Explorer of bricks and scripts: Here

b = true
a = script.Parent.Parent.Part
function onClicked(playerWhoClicked)
	if b == true then
		script.Sound:Stop()
		a.CFrame = a.CFrame + Vector3.new(0, 0.5, 0)
		script.Sound:Play()
		wait(0.1)
		for i=1, 17 do
			a.CFrame = a.CFrame + Vector3.new(0, 0.5, 0)
			wait(0.1)
		b = false
		end
	else
		wait(0.1)
		wait(4)
		script.Sound:Play()
		for i=1 ,18 do
			a.CFrame = a.CFrame + Vector3.new(0, -0.5, 0)
			wait(0.1)
		end
		wait(3)
		b = true
	end
	end
end --Expected <eof>, got 'end'
script.Parent.ClickDetector.MouseClick:connect(onClicked)