Japan mathematical olympiad finals 2006 , problem 4
Source: Japan Mathematical Olympiad Finals 2006 , Problem 4
March 5, 2006
combinatorics proposedcombinatorics
Problem Statement
Let be integers such that and let be integers which are less than or equal to and let be integers which are less than or equal to such that Given a town of the rectangular shaped chessboard which is made up of road running north and south which is called Line and road running west and east which is called Street. Denote the intersection point of the th Line from the west and th Street from the north by , and th Line from the west and th Street from the north by including the edge for both cases.Find all pair of such that by passing through each crossroads of the town exactly one time, you can reach the point from the point including in the start point and goal one.