  (In the revised version the relevant aspect of noncompactness of the moduli
of instantons is discussed. It is shown nonperturbatively that any BRST trivial
deformation of A-model which does not change the ranks of BRST cohomology does
not change the topological correlation functions either) We show that the Floer
cohomology and quantum cohomology rings of the almost Kahler manifold M, both
defined over the Novikov ring of the loop space LM of M, are isomorphic. We do
it using a BRST trivial deformation of the topological A-model. As an example
we compute the Floer = quantum cohomology of the 3-dimensional flag space Fl_3.
