2419.Little Artem and Graph

Time Limit: 1s Memory Limit: 256MB

Little Artem is given a graph, constructed as follows: start with some k-clique, then add new vertices one by one, connecting them to k already existing vertices that form a k-clique.

Artem wants to count the number of spanning trees in this graph modulo 109+7.

Input Format(From the terminal/stdin)

First line of the input contains two integers n and k (1 \le n \le 10000, 1 \le k \le min(n,5))- the total size of the graph and the size of the initial clique, respectively.

Next n-k lines describe k+1-th, k+2-th, ..., i-th, ..., n-th vertices by listing k distinct vertex indices 1 \le aij \lt i it is connected to. It is guaranteed that those vertices form a k-clique.

Output Format(To the terminal/stdout)

Output a single integer- the number of spanning trees in the given graph modulo 109+7.

Sample Input 1

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3 2
1 2
 · \n
 · \n

Sample Output 1

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3
 \n

Sample Input 2

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4 3
1 2 3
 · \n
 · · \n

Sample Output 2

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16
  \n

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