%suma_nr(-X, +Mod)
suma_nr(X, Mod) :-
	read(A),
	prelucrare(A, X, Mod).

%prelucrare(+A, -X, +Mod)
prelucrare(A, X, Mod) :-
	number(A),
	(abs(A) > Mod, suma_nr(Sp, Mod), X is Sp+A; abs(A) =< Mod, suma_nr(X, Mod)).

prelucrare(gata, 0, _).

prelucrare(A, _, _) :-
	atom(A), A \== gata,
	write('eroare'),
	fail.