3060.Permanent

Time Limit: 1s Memory Limit: 256MB

Little X has solved the #P-complete problem in polynomial time recently. So he gives this task to you.

There is a special n \times n matrix A, you should calculate its permanent modulo 1000000007(109+7). The special property of matrix A is almost all its elements equal to 1. Only k elements have specified value.

You can find the definition of permanent at the link: https://en.wikipedia.org/wiki/Permanent

Input Format(From the terminal/stdin)

The first line contains two space-separated integers n,k (1 \le n \le 105;1 \le k \le 50).

The next k lines contain the description of the matrix. The i-th line contains three space-separated integers xi,yi,wi (1 \le xi,yi \le n;0 \le wi \le 109). These numbers denote that Axi,yi=wi. All the elements of the matrix except of the given elements are equal to 1.

It's guaranteed that all the positions (xi,yi) are distinct.

Output Format(To the terminal/stdout)

Print the permanent of the matrix modulo 1000000007(109+7).

Sample Input 1

Copy
3 1
1 1 2
 · \n
 · · \n

Sample Output 1

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8
 \n

Sample Input 2

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10 10
3 3 367056794
6 2 124561273
1 3 46718146
6 9 415916869
10 5 985968336
3 1 526792265
1 4 386357058
10 4 349304187
2 7 102032499
3 6 502679075
  ·  \n
 · ·         \n
 · ·         \n
 · ·        \n
 · ·         \n
  · ·         \n
 · ·         \n
 · ·         \n
  · ·         \n
 · ·         \n
 · ·         \n

Sample Output 2

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233333333
         \n

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