Can you please recheck the problem statement because of disparity  of English and Russion versions. Coordinates of cockroaches are integer without any limitation in russian version, and english version says that all cordinates are real with some restriction on it.

Edited by author 16.06.2007 15:51

And the next sentence is missing in Russian version: "The distance between any two cockroaches is not less than 10−3. Also the distance between any two sweets is not less than 10−3."