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Time Limit: 5 s Memory Limit: 512 MB Total points: 100 Hackable ✓

#900. Maximum Weight Matching in General Graphs

Statistics

Given a simple weighted undirected graph with $N$ vertices and $M$ edges. The $i$-th edge is $(u_i, v_i)$ with weight $w_i$. Find a matching such that the sum of weights is maximized.

Constraints

  • $1 \leq N \leq 500$
  • $0 \leq M \leq \frac{N(N-1)}{2}$
  • $0 \leq u_i, v_i < N$
  • $1 \leq w_i \leq 1\,000\,000$

Input

The input is given in the following format:

  • $N$ $M$
  • $u_0$ $v_0$ $w_0$
  • $u_1$ $v_1$ $w_1$
  • $\vdots$
  • $u_{M - 1}$ $v_{M - 1}$ $w_{M-1}$

Output

The output should be in the following format:

  • $X$ $W$
  • $a_0$ $b_0$
  • $a_1$ $b_1$
  • $\vdots$
  • $a_{X - 1}$ $b_{X - 1}$

$X$ is the size of the maximum matching. $W$ is the maximum matching weight. $(a_i, b_i)$ are the edges of the matching.

Examples

Input 1

7 8
2 0 1
0 5 2
5 6 3
6 1 4
1 0 5
1 3 6
3 4 7
1 4 8

Output 1

3 15
0 1
3 4
5 6

Input 2

4 3
0 2 1
1 3 1
1 2 3

Output 2

1 3
1 2

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