  We give an algorithm which produces infinitely many pairwise exotic Stein
fillings of the same contact 3-manifolds, applying positive allowable Lefschetz
fibrations over the disk. As a corollary, for a large class of Stein fillings,
we realize the topological invariants (i.e. fundamental group, homology group,
homology group of the boundary, and intersection form) of each filling as those
of infinitely many pairwise exotic Stein fillings. Furthermore, applying the
algorithm, we produce various contact 3-manifolds of support genus one each of
which admits infinitely many pairwise exotic Stein fillings.
