Hi all. I would like to replace the hyphen between two numerals with an en dash.

Example of Original String:
12-18

Desired Output:
12–18

My Wildcard Search:

Find: (-)([0-9])
Replace: –\2

Output is 121–8 instead of the desired 12–18. Could you kindly give my brain a nudge--what am I missing? Thank you in advance for any info or assistance!