if(Prover9). % Options for Prover9
  assign(max_seconds, 60).
end_if.

if(Mace4).   % Options for Mace4
  assign(max_seconds, 60).
end_if.

formulas(assumptions).

all x (-rich(x) & man (x) -> rich(father(x))).
all x (man(x) -> man (father(x))).
all x (man(x) -> exists y (father(x) = y)).
exists x (man(x)).

end_of_list.

formulas(goals).

exists y (rich(y) & man(y) & rich(father(father(y)))).

end_of_list.