It is about the constraint programming. We have party organizations for being social. Each participant has their own preference list for parties, every party organizers has their own preference list for providing the parties. We know minimum # of and max # of parties that participant must join. Each party and each organizer have the capacities. We know min # of and max # of capacities. Within this situation, which parties will be offered and who will provide and who will join parties? How we can model this problem? Our purpose is to maximize the happiness.