$2022$ and $2020$. Claim.$1$: If we colour the edges of $K_n$ with at least $n$ colours, there gonna be a triangle which has all edges in different colours. Proof: Double counting for monochromatic angles. Claim.$2$: If we colour the edges of $K_n$ with at most $n-3$ colours, there gonna be a cycle of lenght $3$ or $4$ which has all edges in the same colour. Proof: Take the vertex with maximal neighbours in the same colour (which should be greater than $4$ by PHP.). And take another neighbour of that vertex which has the edges between them is in different colour (we also can assume such vertex exist bcs otherwise we can do induction to $n$.). Then the contradiction comes immedietly.