Question 27
A directed graph $G$ has 2021 vertices located on a circle, 101 directed edges go from each vertex of $G$ to the next 101 vertices in the counter-clockwise direction. We wish to colour the edges in such a way that for any two vertices $u$ and $v$ one can choose a directed path from $u$ to $v$ in which no two edges have the same colour. What is the minimum number of colours needed?