1. Dorodnicyn Computing Centre of the Russian Academy of Sciences, Moscow 119333, Russia and Sternberg Astronomical Institute, MSU, Moscow 119992, Russia. E-mail: sergeyib@pochta.ru
2. Lomonosov Moscow State University, Moscow 119899, Russia and Moscow Institute of Physics and Technology, Moscow Oblast' 141700, Russia. E-mail: alexandre.demidov@mtu-net.ru