1. Division of Mathematical and Computer Science and Engineering, King Abdullah University of Science and Technology, P.O. Box 55455, Jeddah 21534, Saudi Arabia. mikhail.moshkov@kaust.edu.sa
2. ING Bank Śl�ski S.A. 34, Sokolska St., Katowice 40-086, Poland. marcin.piliszczuk@ingbank.pl
3. Institute of Computer Science, University of Silesia 39, B�dzińska St., Sosnowiec 41-200, Poland. beata.zielosko@us.edu.pl