A man with a backpack and two children are on the beach.
A man does not have his children at the beach.
Two children cannot be at the beach if a man does not have his children there.
exists p1 x1 x2 x3 x4.(n_beach(x4) & on(x1,x4) & with(x1,x2) & n_child(x2) & card_eq_2(x2) & of(x2,x3) & n_backpack(x3) & n_man(x1))
exists x1 x2 x3.(n_beach(x3) & -exists e1.(at(e1,x3) & Theme(e1,x2) & Actor(e1,x1) & v_have(e1)) & n_child(x2) & of(x2,x1) & n_male(x1) & n_man(x1))