B'You are given three integers n , d and k . Your task is to construct an undirected tree on n vertices with diameter d and degree of each vertex at most k , or say that it is impossible. An undirected tree is a connected undirected graph with n - 1 edges. Diameter of a tree is the maximum length of a simple path (a path in which each vertex appears at most once) between all pairs of vertices of this tree. Degree of a vertex is the number of edges incident to this vertex (i.e. for a vertex u it is the number of edges (u, v) that belong to the tree, where v is any other vertex of a tree). The first line of the input contains three integers n , d and k ( 1 <= n, d, k <= 4 cdot 10^5 ). If there is no tree satisfying the conditions above, print only one word "NO" (without quotes). Otherwise in the first line print "YES" (without quotes), and then print n - 1 lines describing edges of a tree satisfying the conditions above. Vertices of the tree must be numbered from 1 to n . You can print edges and vertices connected by an edge in any order. If there are multiple answers, print any of them.1 '...