Problem 5 of Third round - Getting a monochromatic coloring of an n-gon
Source: I International Festival of Young Mathematicians Sozopol 2010, Theme for 10-12 grade
December 14, 2019
combinatoricspolygonColoring
Problem Statement
Each vertex of a right -gon is colored in yellow, blue or red. On each turn are chosen two adjacent vertices in different color and then are recolored in the third. For which can we get from an arbitrary coloring of the -gon a monochromatic one (in one color)?