A little suggestion to make things more robust. It doesn't matter with your sample data but it might matter with different data.
In columns B&C you might have:
1381 and 38"24
and in columns K & L you might have somewhere:
13813 and 8"24
When the two pairs are concatenated they both look the same:
138138"24
but they're not actually a match but the current formula would say it is a match.


That can be corrected by changing from:
to:
Now one looks like:
1381¬38"24
and the other:
13813¬8"24
so they aren't a match any more.

It doesn't have to be that ¬ character, a space would be almost as good; any character that you wouldn't expect to see in the data would be best.