Three system with impulse with impulse responses h1(n) = (n) (n - 1), h2(n) = h(n),

Question:

Three system with impulse with impulse responses h1(n) = δ(n) – δ(n - 1), h2(n) = h(n), and h3 (n) = u (n), are connected in cascade.
(a) What is the impulse response, h0(n), of the overall system?
(b) Does the order of the interconnection affect the overall system?