Q1) It is about constraint programming. We have party organizations for being social. Every participant has their own preference list for parties, every party organizers has their own preference list for giving parties, too. We know minimum # of and max # of parties which participant should join. Each party and each organizer have capacities. We know min # of and max # of capacities. In this situation, which parties will be given and who will give and who will join parties? How can we model this problem? Our aim is maximizing happiness.