Uzycie not_member zamiast not(member(...)) iss#2

Poprawia nieznacznie czas:
mala:    298,494 inferences, 0.062 CPU in 0.060 seconds (104% CPU,4783527 Lips)
duza: 12,926,917 inferences, 2.496 CPU in 2.490 seconds (100% CPU,5179020 Lips)