1:- use_module(library(pita)).    2
    3
    4:- pita.    5
    6:- begin_lpad.    7
    8a:0.5.
    9
   10b:0.5.
   11
   12p:0.3:-a,b.
   13
   14p:0.7:- \+ a,b.
   15
   16p:0.4:- \+ a,\+ b.
   17
   18p:0.6 :- a,\+b.
   19
   20evidence:-p,b.
   21
   22a_b:-a,b.
   23a_nb:-a,\+b.
   24na_b:- \+a,b.
   25na_nb:- \+a,\+b.
   26
   27:- end_lpad.