It can also be said to be an AA system. Everyone contributes 100 or more. Anyway, everyone has the same amount and pools together a fund. A responsible classmate will be responsible for the money. Funds are basically used to pay for gatherings. If you pay money, it will not be refunded if you do not attend the party. This is more fair, and it doesn't require everyone to dig into their pockets after each party, so it's calculated separately.