I do not know how to use regex in c#. I'm confused.
Here is the URL where i want to exact the id:

<https://j-ec.static.com/images/385/>**3858715**.jpg

I just want to get the bolded number.

The regex I try to use is:

```
Match thumb_id = Regex.Match(url, @"\/(?)\.jpg");

```

What's wrong?

Any help?