I have a list of values that contains various values, but I'm only interested in the number after # of those starting with XXX\_

```
ABC

XXX_YYY

XXX_YYY#12235

XXX_YYY#12281

XXX_YYY#12318

```

I have tried several things but not quite hit the head of the nail :-(

```
(?<!XXX\_)#

```

and

```
(?<=XXX\_)\*\[^#\]+$ - closest but also get those without # in :-(

```