  Contribution of the gluon distribution in the nucleon to the cross section
for the pion diffractive dissociation into two jets has been calculated
recently. In addition, we present here calculation of contribution of the quark
distributions to this process.
  It is expected usually that the quark contributions are much smaller than the
gluon one at high energies. We show that, under the conditions of the E791
experiment, the quark contributions are as significant as the gluon one, so
that the total cross section exceeds several times those with only gluon
contribution.
  Nevertheless, the distribution of jets in longitudinal momentum fractions
does not change significantly and remains qualitatively the same. We compare
our results with the data from the E791 experiment.
