PolandBall lives in a forest with his family. There are some trees in th...

Severe acute respiratory syndrome (SARS), an atypical pneumonia of unkno...

In this problem you will be given several descriptions of collections of...

Given two positive integers a and b,find suitable X and Y to meet the co...

Ilya is an experienced player in tic-tac-toe on the4 × 4field. He always...