This solution was submitted and prepared by stundent named above for the home assignment of the Web engineering course. I declare that this solution is my own work. I have not copied or used third party solutions. I have not passed my solution to my classmates, neither made it public. Students’ regulation of Eötvös Loránd University (ELTE Regulations Vol. II. 74/C. § ) states that as long as a student presents another student’s work - or at least the significant part of it - as his/her own performance, it will count as a disciplinary fault. The most serious consequence of a disciplinary fault can be dismissal of the student from the University.