Update instructions.md

Co-authored-by: Anastasios Chatzialexiou <[email protected]>

Author: ErikSchierboom

exercises/baffling-birthdays/instructions.md

@@ -6,7 +6,7 @@ To do this, you need to:
 
 - Determine if two birthdates have the same month and day.
 - Generate random birthdates.
-- Check if a collection of randomly generated birthdates contains at least one matching pair.
+- Check if a collection of randomly generated birthdates contains any two with the same month and day.
 - Estimate the probability of at least one match for different group sizes.
 
 ~~~~exercism/caution