Both black bullets PLS

Suppose a byte$-$addressable computer using set associative cache has $2^(21)$ bytes of main memory and a cache of $64$ blocks, where each cache block contains $4$ bytes.

a$.$ If this cache is $2-$way set associative, what is the format of a memory address as seen by the cache; that is$,$ what are the sizes of the tag, set, and offset fields?

b$.$ If this cache is $4-$way set associative, what is the format of a memory address as seen by the cache?