You have a large collection of sloths that can be classified into different levels of cuteness numbered 1-5, where 1 is mildly cute, 2 is pretty cute, 3 is substantially cute, 4 is dangerously cute, and 5 is apocalyptically cute. Assume that you have an infinite number of sloths in each category (wooo!), and that all sloths in each category are indistinguishable from one another.

a) How many multisets of 20 sloths can you create out of your collection?
b) How many multisets of 20 sloths are possible if you want to guarantee that at
least 7 mildly cute sloths are selected? (Hint: Start by picking 7 mildly cute sloths, then
think about how to select the remaining sloths.)