%% either taking the bus or the train to school 

desire(L):- literal(L).

desire(or1).
isor(or1, obus, otrain).

desire(obus).
happen(obus, bus(station, school)).

desire(otrain).
happen(otrain, train(station, school)).

desire(d1).
eventually(d1, or1).

maximize {satisfy(d1,0)}.