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A11004 | Mister B and Flight to the Moon

时间限制1s
内存限制256MB
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题目描述

In order to fly to the Moon Mister B just needs to solve the following problem.

There is a complete indirected graph with $n$ vertices. You need to cover it with several simple cycles of length $3$ and $4$ so that each edge is in exactly $2$ cycles.

We are sure that Mister B will solve the problem soon and will fly to the Moon. Will you?

输入格式

The only line contains single integer $n$ ( $3<=n<=300$ ).

输出格式

If there is no answer, print -1.

Otherwise, in the first line print $k$ ( $1<=k<=n^{2}$ ) — the number of cycles in your solution.

In each of the next $k$ lines print description of one cycle in the following format: first print integer $m$ ( $3<=m<=4$ ) — the length of the cycle, then print $m$ integers $v_{1},v_{2},...,v_{m}$ ( $1<=v_{i}<=n$ ) — the vertices in the cycle in the traverse order. Each edge should be in exactly two cycles.

输入输出样例

输入 #1
3
输出 #1
2
3 1 2 3
3 1 2 3
输入 #2
5
输出 #2
6
3 5 4 2
3 3 1 5
4 4 5 2 3
4 4 3 2 1
3 4 2 1
3 3 1 5
C++ 编辑器
输入
输出