How do I make this script show how many enemies are left?

print 'WavetimerGUI script loaded'

game.ReplicatedStorage.Alien.Parent = game.Workspace game.StarterGui.WaveCounterGUI.Frame.Text = "Martians left:

Use a for in pairs loop!

Number = 0
for i, v in pairs(Workspace:GetChildren) do
	if v.Name == "Alien" then
		Number = Number + 1
	end
end
print(Number)