  We consider the question about the number of master integrals for a multiloop
Feynman diagram. We show that, for a given set of denominators, this number is
totally determined by the critical points of the polynomials entering either of
the two representations: the parametric representation and the Baikov
representation. In particular, for the parametric representation the
corresponding polynomial is just the sum of Symanzik polynomials. The relevant
topological invariant is the sum of the Milnor numbers of the proper critical
points. We present a Mathematica package Mint to automatize the counting of the
master integrals.
