You are given a positive integer K≤60. Construct a graph with at most 20 vertices with the following property: there are exactly K unordered pairs of vertices (u,v) such that there is a Hamiltonian path between u and v in this graph.
It can be shown that, under these constraints, the solution always exists.
Recall that a Hamiltonian path is a path between two vertices of a graph that visits each vertex exactly once.
The only line of the input contains a single integer K (1≤K≤60).
On the first line, output two integers n and m (2≤n≤20, 0≤m≤2n(n−1)), the number of vertices and the number of edges in your graph respectively.
In each of the next m lines, output two integers u and v (1≤u,v≤n, u=v), representing the edge (u,v) of your graph. All edges have to be distinct.