Use a Venn Diagram and the given information to determine the number of elements in the indicated set.
$n(U) = 83$, $n(A) = 31$, $n(B) = 40$, $n(C) = 24$, $n(A \cap B) = 7$, $n(A \cap C) = 8$, $n(B \cap C) = 6$, and $n(A \cap (B \cap C)) = 4$. Find $n((A \cup B \cup C)')$.