Order of injectors?

Greetings,

So I've posted previously about a problem I'm getting frequently with the car going into limp mode with error message injection fault.
I've decided to first send the injectors for servicing since my obd scanner says there's a specific error message saying injector no.4 circuit.

I took out the injectors yesterday, was an easier job than I expected thanks to the manual I got from this forum.

Now just would like to ask which end in the picture is injector no. 4? The input nozzle that connects to the fuel hose is on the left in the picture. That's also how it looks in the engine bay.