And I would like to tell you one of the problems I solved, of which I am prac- I am very proud, because- not only my solution but the way how I solved it, I found to my great pleasure a few years ago, has become a legend in Hungary. The problem was this: you have a glass of water and you have an ice cube floating into it- flowing- floating in it. Question: If the ice cube melts, otherwise no change in temperature, by how much will the level of water rise? Now, I remember clearly I read this and within a couple of seconds I heard a memo - a melody. I will not do the favor to you of singing it, I could, but it's a favor if I don't. Unfortunately, I can't even tell you the text because it's Hungarian. It's a famous Hungarian text and it is really a theorem. A body on the water will lose of its weight just as much as the weight of the displaced water, that is the melody. And of course, once you remember that, the rest is easy. Take out the ice cube, you leave a hole. Melt the ice cube, put it into the hole, the ice cube had floated, therefore it had to weigh just as much as the weight of the water that it has displaced. It became that water, and therefore it filled just that hole. And the answer to the question is: the level of water did not rise. That was, in a way, my first success as a scientist.