We investigate binary voting systems with two types of voters and a hierarchy among
the members in each type, so that members in one class have more influence or importance
than members in the other class. The purpose of this paper is to count, up to isomorphism,
the number of these voting systems for an arbitrary number of voters. We obtain a closed formula for the number of these systems, this formula follows a Fibonacci sequence with a smooth polynomial variation on the number of voters.