  The artificial neural network approach is used for separation of signals from
a single photon $\gamma$ and products of the $\pi^0,\eta, K^0_s$ meson neutral
decay channels on the basis of the data from the CMS electromagnetic
calorimeter alone. Rejection values for the three types of mesons as a function
of single photon selection efficiencies are obtained for two Barrel and one
Endcap pseudorapidity regions and initial $\Et$ of 20, 40, 60 and 100 GeV.
