  We show that minimal models of nondegenerated hypersufaces defined by Laurent
polynomials with a $d$-dimensional Newton polytope $\Delta$ are Calabi-Yau
varieties $X$ if and only if the Fine interior of $\Delta$ consists of a single
lattice point. We give a combinatorial formula for computing the stringy Euler
number of $X$. This formula allows to test mirror symmetry in cases when
$\Delta$ is not a reflexive polytope. In particular we apply this formula to
pairs of lattice polytopes $(\Delta, \Delta^{\vee})$ that appear in the
Mavlyutov's generalization of the polar duality for reflexive polytopes. Some
examples of Mavlyutov's dual pairs $(\Delta, \Delta^{\vee})$ show that the
stringy Euler numbers of the corresponding Calabi-Yau varieties $X$ and
$X^{\vee}$ may not satisfy the expected topological mirror symmetry test:
$e_{\rm st}(X) = (-1)^{d-1} e_{\rm st}(X^{\vee})$. This shows the necessity of
an additional condition on Mavlyutov's pairs $(\Delta, \Delta^\vee)$.
