Two players i and j are substitutes in a game (N, w) if their contributions to all

Question:

Two players i and j are substitutes in a game (N, w) if their contributions to all coalitions are identical, that is, if
W(S ∪ {i}) = w(S ∪ {j} for every S ⊆ N \ {i, j}
Verify that the Shapley value treats substitutes symmetrically, that is i j substitutes ⇒ ϕiw = ϕjw