What is the correct way to write a LibreOffice regular expression?

Question

Regular Expressions

The LibreOffice table contains the names of products with the quantity in the package.
Examples:
product number one 50 ml container, 60 pcs.
item number two packing 100 pcs.
item number three 10pcs.
It is necessary to leave only the number of pieces in the package in the cells, and delete everything else, that is:
60 pieces
100 pieces
10 pieces
I try different regular expressions, but nothing helps.
([^0-9]{1,3}) ([^т-ш])
[![0-9]{1,3}[:space:][:lower:]{2}]
Please help me write a regular expression.
Thank you!

Answer 1

it's all right?
\d* ?pcs