摘要：
Masha has recently bought a cleaner robot, it can clean a floor without anybody's assistance. Schematically Masha's room is a rectangle, consisting of 阅读全文
摘要：
A gourmet came into the banquet hall, where the cooks suggested n dishes for guests. The gourmet knows the schedule: when each of the dishes will be s 阅读全文
摘要：
Welcoming autumn evening is the best for walking along the boulevard and npeople decided to do so. The boulevard can be represented as the axis Ox. Fo 阅读全文