E. Tree Constructing
time limit per test
4 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output

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).

Input

The first line of the input contains three integers $$$n$$$, $$$d$$$ and $$$k$$$ ($$$1 \le n, d, k \le 4 \cdot 10^5$$$).

Output

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

Examples
Input
6 3 3
Output
YES
3 1
4 1
1 2
5 2
2 6
Input
6 2 3
Output
NO
Input
10 4 3
Output
YES
2 9
2 10
10 3
3 1
6 10
8 2
4 3
5 6
6 7
Input
8 5 3
Output
YES
2 5
7 2
3 7
3 1
1 6
8 7
4 3