Well, I studied chemistry as I was supposed to but I cheated, I really cheated - I studied mathematics as well and with great pleasure. I remember one vacation which I spent at home in Budapest by thinking about one set of problems in mathematics, which I love so much that I would like to mention it. I did not discover anything that people would not know but I essentially reconstructed the essential parts of it from the simple principles. The subject is called Set Theory. And set theory becomes interesting when you do not compare a set of five objects with another set of five objects but if you compare a set of infinitely many objects with another set and the remarkable result is that there are different kinds of infinity. I think I should tell you, without a proof, the kind of thing set theory is made of. Question: are there more points on a line than there are integers? The answer turns out to be yes - not very surprising. Second question: are there more points on a line than the number of fractions which can be written as one integer over another integer. The answer is again, yes. Continuous infinity, the infinity in a continuum of points, is greater. And these ideas can be defined precisely and a group of theorems can be deduced, which is what I dug into in one of the three weeks period that I was at home.