A $solar flare$ is a phenomenon where the sun suddenly releases a great amount of solar radiation, much more than normal. In total, there are n possible wavelengths of radiations and there are m different types of radiation . The total effect of $solar flare$ is total number of distinct arrangement of wavelength of radiations. As the total number can be large , you have to report the answer mod $10^{9}+7$ .

Arrangement $A_{1},A_{2}......A_{n}$ and $B_{1},B_{2}......B_{n}$ is said to be different if for any i, $1 \le i \le n$ , $A_{i}$ $\neq$ $B_{i}$

Input :

First line contains n and m

Next line contains an array of M elements, denoting number of radiations of $i^{th}$ type

Output :

Output Number of distinct arrangements modulo $10^{9}+7$

Constraints

$1 \le n,m\le 10^{6}$

$0 \le A_{i} \le 10^{6}$