The boy is looking up at the girl as another girl ignores them.
There is one boy and two girls.
Sentence 1 refers to a boy, a girl, and another girl.  Therefor there is one boy and two girls.
exists e1 p1 s1 x1 x2.(n_thing(x2) & n_girl(x2) & n_girl(x2) & n_boy(x1) & exists e2 x3.(Theme(e2,x2) & Actor(e2,x3) & v_ignore(e2) & n_girl(x3) & -(x3 = x2)) & as(e1,p1) & a_up(s1) & Manner(e1,s1) & at(e1,x2) & Actor(e1,x1) & v_look(e1))
exists p1 x1 x2 x3 x4.((x1 = x2) & n_girl(x4) & card_eq_2(x4) & n_boy(x3) & subset_of(x4,x2) & subset_of(x3,x2) & card_eq_1(x2))