1. Faculty of Computation Mathematics and Cybernetics, Lomonosov Moscow State University, 119991 Moscow, Russia
2. Moscow Center of Fundamental and Applied Mathematics, 119234 Moscow, Russia
3. Department of Mathematical and Applied Analysis, Voronezh State University, 394018 Voronezh, Russia
4. Department of Applied Mathematics and Computer Modeling, Belgorod State National Research University (BelGU), 308015 Belgorod, Russia