Alliance merge question

I’m in season 1 currently and there is an option for Alliance Merge. Can someone tell me how many members total can an alliance possibly have? My alliance can hold a member of 72 members but only have 42 at the moment. The alliance I want to merge with has 60 players max. Can we merge and the members get added together? Or will the other alliance need to get rid of inactive players first to lessen the amount of players that come over?