Formula tool. Not working

[XXX_Rosy_XXX]

I have a column name [Booked by Staff ID] those have any alphabest actually belong to student ID and just number is staff ID. 

 the below syntax is not working. i have an error. Please help. What other ways or tools can I use?

if contains([Booked By Staff ID],REGEX_Match([Booked By Staff ID], '^\d+')
THEN "Student"
ELSE "Staff"
ENDIF

[Qiu · Accepted solution]

@XXX_Rosy_XXX 
I dont think we need the Contain function here, try below.

if REGEX_Match([Booked By Staff ID], '^\d+')
THEN "Student"
ELSE "Staff"
ENDIF