16-th summer conference International mathematical Tournament of towns

Belarus, Mir, 01.08.2004-09.08.2004.

Problem 1. "12"

Problem proposed by V. Prasolov, M. Skopenkov and S. Dorichenko.

Tasks and solutions

3 pages - tasks before the semifinal (given at begining of conference 01.08.2004) 3 pages (it is given 04.08.2004 - after the semifinal): 10 pages - tasks, solutions, additional materials (the full version prepared by jury to the ending of conference):