题目描述
Mole decided to live in an abandoned mine. The structure of the mine is represented by a simple connected undirected graph which consists of N vertices numbered 1 through N and M edges. The i-th edge connects Vertices a_i and b_i, and it costs c_i yen (the currency of Japan) to remove it.
Mole would like to remove some of the edges so that there is exactly one path from Vertex 1 to Vertex N that does not visit the same vertex more than once. Find the minimum budget needed to achieve this.
Constraints
- $2 \leq N \leq 15$
- $N-1 \leq M \leq N(N-1)/2$
- $1 \leq a_i, b_i \leq N$
- $1 \leq c_i \leq 10^{6}$
- There are neither multiple edges nor self-loops in the given graph.
- The given graph is connected.
Input
Input is given from Standard Input in the following format:
N M
a_1 b_1 c_1
:
a_M b_M c_M
Output
Print the answer.
Examples
Input
4 6
1 2 100
3 1 100
2 4 100
4 3 100
1 4 100
3 2 100
Output
200
Input
2 1
1 2 1
Output
0
Input
15 22
8 13 33418
14 15 55849
7 10 15207
4 6 64328
6 9 86902
15 7 46978
8 14 53526
1 2 8720
14 12 37748
8 3 61543
6 5 32425
4 11 20932
3 12 55123
8 2 45333
9 12 77796
3 9 71922
12 15 70793
2 4 25485
11 6 1436
2 7 81563
7 11 97843
3 1 40491
Output
133677
输入格式
见题面
输出格式
见题面