VK Cup 2016 - Round 2 |
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Finished |

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G. Little Artem and Graph

time limit per test

12 secondsmemory limit per test

256 megabytesinput

standard inputoutput

standard outputLittle 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 10^{9} + 7.

Input

First line of the input contains two integers *n* and *k* (1 ≤ *n* ≤ 10 000, 1 ≤ *k* ≤ *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 ≤ *a*_{ij} < *i* it is connected to. It is guaranteed that those vertices form a k-clique.

Output

Output a single integer — the number of spanning trees in the given graph modulo 10^{9} + 7.

Examples

Input

3 2

1 2

Output

3

Input

4 3

1 2 3

Output

16

Codeforces (c) Copyright 2010-2024 Mike Mirzayanov

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