Given the degrees of the vertices of the graph and the number K. It is necessary to construct a graph with such degrees of vertices that if you remove any K edges in it, it remains connected, or say that there is no such graph. If the degrees of all vertices are greater than K, we simply do the following algorithm: a vertex of the minimum degree, cross it out from the list and connect it with vertices of the maximum degree. This works and really maximizes the edge connectivity of the graph, but why?