and r = 5 (the number of friends). So we have: Stars and Bars(90,5) = (90+5-1) ! / ((5-1)-! (90-1)!)

5. Finally, we multiply this result by the number of ways to arrange the friends without M&Ms (which is 5! = 120 if we allow for zero bars). So the total number of ways to distribute 90 M&Ms among 5 friends with at least one M&M each is: Total Ways = Stars and Bars(90,5) * 5!