Tip #1: Remember how John said to draw a hierarchy with officers at the top.

Tip #2: The "or" part of this is a little strange, but the idea is that the "2 officers" part means that for every officer you choose, you are indirectly choosing 3 sergeants, for a total of 6 sergeants, all of which are under only 2 officers' command.

Tip #3:  The "6 sergeants" part means that you can choose ANY 6 sergeants, regardless whether or not they are under the same 2 officers.

Tip #4:  If you are stuck, try rewatching the lecture at this part!