Exclude <span> from <h2> using not:()

How to?
#1

I want to exclude span from h2, specificaly from h2#market-item-name, i try with :not(span), :not(.tooltip a), not:(span.tooltip), not:(.tooltip tooltipstered) but nothing works for me. The only thing i want is the plain text "2138"

this is the HTML of h2:

<h2 id="market-item-name"><img src="/data/items/icons2/2138.png" width="24px" height="24px">
	<span class="tooltip tooltipstered" data-tooltip-content="#tooltip_content"><a href="#" onclick="if (!window.__cfRLUnblockHandlers) return false; return false;">Bradium Shield [1]</a></span> • 2138 </h2>

not excluding sitemap:

{"_id":"copia","startUrl":["https://www.novaragnarok.com/?module=vending&action=item&id=2138"],"selectors":[{"id":"Item","type":"SelectorText","parentSelectors":["_root"],"selector":"h2#market-item-name","multiple":false,"regex":"","delay":0}]}

#2

Due to site's HTML structure, you can't use Not for this case, But a regex should work.

Type: Text
Selector: h2#market-item-name
Regex: \d{1,5}$

This will get all numbers at the end, from 0 to 99999.

#3

thank you very much, gonna try it now. Is there any guide fully explaining how regex works?