CF916C.Jamie and Interesting Graph

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题目描述

Jamie has recently found undirected weighted graphs with the following properties very interesting:

  • The graph is connected and contains exactly nn vertices and mm edges.
  • All edge weights are integers and are in range [1,109][1,10^{9}] inclusive.
  • The length of shortest path from 11 to nn is a prime number.
  • The sum of edges' weights in the minimum spanning tree (MST) of the graph is a prime number.
  • The graph contains no loops or multi-edges.

If you are not familiar with some terms from the statement you can find definitions of them in notes section.

Help Jamie construct any graph with given number of vertices and edges that is interesting!

输入格式

First line of input contains 2 integers nn , mm — the required number of vertices and edges.

输出格式

In the first line output 2 integers spsp , mstwmstw (1<=sp,mstw<=1014)(1<=sp,mstw<=10^{14}) — the length of the shortest path and the sum of edges' weights in the minimum spanning tree.

In the next mm lines output the edges of the graph. In each line output 3 integers uu , vv , ww (1<=u,v<=n,1<=w<=109)(1<=u,v<=n,1<=w<=10^{9}) describing the edge connecting uu and vv and having weight ww .

输入输出样例

  • 输入#1

    4 4
    

    输出#1

    7 7
    1 2 3
    2 3 2
    3 4 2
    2 4 4
    
  • 输入#2

    5 4
    

    输出#2

    7 13
    1 2 2
    1 3 4
    1 4 3
    4 5 4
    

说明/提示

The graph of sample 1: Shortest path sequence: 1,2,3,4{1,2,3,4} . MST edges are marked with an asterisk (*).

Definition of terms used in the problem statement:

A shortest path in an undirected graph is a sequence of vertices (v1,v2,... ,vk)(v_{1},v_{2},...\ ,v_{k}) such that viv_{i} is adjacent to vi+1v_{i+1} 1<=i<k1<=i<k and the sum of weight is minimized where w(i,j)w(i,j) is the edge weight between ii and jj . (https://en.wikipedia.org/wiki/Shortest_path_problem)

A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself. (https://en.wikipedia.org/wiki/Prime_number)

A minimum spanning tree (MST) is a subset of the edges of a connected, edge-weighted undirected graph that connects all the vertices together, without any cycles and with the minimum possible total edge weight. (https://en.wikipedia.org/wiki/Minimum_spanning_tree)

https://en.wikipedia.org/wiki/Multiple_edges

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