Help wanted about permalinks in Lesson 3

[DingFanYun]

In lesson 3 Yaro talked about optimizing permalinks in his video.
I know I should change from Default to Customize and type in something.
However I can't see what exactly Yaro had typed in his custom structure because the video was kind of blurry and the words are too small to be seen clearly.
Anyone who knows what Yaro had put in his Custom structure? I only know this could show the post numbers and post names.

[Blaine Moore]

Yaro uses this, I believe:

/%post_id%/%postname%/

[DingFanYun]

Got it. Thank you so much!

[proson]

I would use this

/%category%/%postname%/

for better structing and also SEO.