Brown AB and ScB majors both require 2 introductory CS courses and 3 intermediate CS courses. The AB major requires 4 advanced CS courses, while the ScB major requires 8 advanced CS courses plus 2 math courses beyond the calculus 2 level (note that discrete math is listed in the CS department as an intermediate CS course). So a total of 9 CS courses for the AB major versus 13 CS courses and 2-4 math courses (15-17 total) for the ScB major. Brown requires a minimum of 30 courses to graduate, though 32 is probably more typical based on 4 courses per semester over 8 semesters.
https://cs.brown.edu/degrees/undergrad/concentrations/ab_reqs/
https://cs.brown.edu/degrees/undergrad/concentrations/scb_reqs/