:- use_module(library(clpfd)).

sumator([A,B],[FW,FR,FM]) :-
   InOut = [A,B,FW,FR,FM],
   InOut ins 0..1,
   FW #<==> (A #\/ B)  #/\ A,
   FR #<==> #\ (A #/\ B)),
   FM #<==> (A #\/ B)  #/\ B
   labeling([],InOut).