PHP regEX pattern(href) required?

I used PHP cURL to get an html from a web page then i need to get all the digits from an href using regEX , but actually i don't have the correct pattern

href tag:

<a href="/en/jordan/jobs/economic%2drecovery%2dand%2ddevelopment%2derd%2dmonitoring%2dofficer%2d3579748/"><span itemprop="title">Economic Recovery and Development (ERD) Monitoring Officer</span></a>

Like --->> only the digits 3579748

but i need to do that for all of href tags i have anybody help me please ?