  We study a crossover from classical to quantum picture in the electron energy
statistics in a system with broken time-reversal symmetry. The perturbative and
nonperturbative parts of the two level correlation function, $R(\omega)$ are
analyzed. We find that in the intermediate region, $\Delta\ll\omega\sim
t_E^{-1}\ll t_{erg}^{-1}$, where $t_E$ and $t_{erg}$ are the Ehrenfest and
ergodic times, respectively, $R(\omega)$ consists of a series of oscillations
with the periods depending on $t_E$, deviating from the universal Wigner-Dyson
statistics. These Ehrenfest oscillations have the period dependence as
$t_E^{-1}$ in the perturbative part. [For systems with time-reversal symmetry,
this oscillation in the perturbative part of $R(\omega)$ was studied in an
earlier work (I. L. Aleiner and A. I. Larkin, Phys. Rev. E {\bf 55}, R1243
(1997))]. In the nonperturbative part they have the period dependence as
$(\Delta^{-1}+\alpha t_E)^{-1}$ with $\alpha$ a universal numerical factor. The
amplitude of the leading order Ehrenfest oscillation in the nonperturbative
part is larger than that of the perturbative part.
