I got a syntax error(I think) and I can't find. Can you tell what I did?

I got this error {Expected 'end' (to close 'function' at line 4), got 'else'}.

I'm sorry if this is a really simple and easy solution, but I don't know. I made a simple sprint and it worked and then I continued to work on it so that the player change the speed back to normal. But then I got this error and it stopped working.

This is my script in its entirety:

local var_x = 0
while true do
	wait(1)
	game:GetService("UserInputService").InputBegan:Connect(function(input, gameProcesed)
    	if var_x == 0 then
		if input.KeyCode == Enum.KeyCode.X then 
        		game.Player.LocalPlayer.Character:WaitForChild("Humanoid").WalkSpeed = 50
			local var_x = 1 
    		end 
	end
	else then
		if input.KeyCode == Enum.KeyCode.X then 
        		game.Player.LocalPlayer.Character:WaitForChild("Humanoid").WalkSpeed = 17
			local var_x = 0 
    		end 
	end			
end

I know it's just a simple sprint button but I'm still confused.