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A11954 | Tree Constructing

时间限制1s
内存限制256MB
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题目描述

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

输入格式

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.

输出格式

无

输入输出样例

输入 #1
6 3 3
输出 #1
YES
3 1
4 1
1 2
5 2
2 6
输入 #2
6 2 3
输出 #2
NO
输入 #3
10 4 3
输出 #3
YES
2 9
2 10
10 3
3 1
6 10
8 2
4 3
5 6
6 7
输入 #4
8 5 3
输出 #4
YES
2 5
7 2
3 7
3 1
1 6
8 7
4 3
C++ 编辑器
输入
输出