What could I do to find a value that matches many different lists.

For example, if I wanted to find something that matches many different lists.
I have many variables with different lists. Could I make it so that I can find a item from a list that matches the variable criteria. Like, X is not in list 1, is in list 2, not in list 3, is in list 4, is in list 5, and pull the item that mathces the criteria.

List1 = [1, 2, 4, 5]
List2 = [2, 3, 5, 6]
List3 = [2, 5, 4]
List4 = [3, 16, 20]
List 5 = [3, 4, -4]

How could I make a script to find 3?