% a)

decr(X,NX) :-
    NX is X-1.

tabela(X, L1) :-
	helper(X, [z], L1).
helper(0, L1, L1).
helper(X, L, L2) :-
	decr(X, C),
	append([s], [L], L1),
	helper(C, L1, L2).

% b)

incr(X,NX) :-
    NX is X+1.

vsota(0, Y, Z) :- Z is Y.
vsota(X,Y,Z) :-
	decr(X, C1),
	incr(Y, C2),
	vsota(C1, C2, Z).

% c)

zmnozek(X,Y,Z) :-
	Z is X*Y.

% d)

stevilo(0, _).
stevilo(N,X) :-
	C is N-1,
	append([1], X, L1),
	stevilo(C, L1).