p(1..300).
aa :- not bb.
bb :- not aa.
pa(X) :- aa, p(X).
pb(X) :- bb, p(X).
a(X,Y) :- pa(X), pa(Y), p(X), p(Y), not b(X,Y).
b(X,Y) :- pb(X), pb(Y), p(X), p(Y), not c(X,Y).
c(X,Y) :- a(X,Y), p(X), p(Y), X<Y.
:- aa.