#include<bits/stdc++.h>
#define ll long long
using namespace std;
const ll MOD=1e9+7;
const int N=1e6+2;
ll a[N];
ll f[N];
ll niyuan[N];
ll ans;
ll tn;
ll n,m,cnt;
ll fastpow(ll x,ll deep){
	if(deep==1)return x;
	ll tmp=fastpow(x,deep/2)%MOD;
	if(deep%2==0){
		return (tmp*tmp)%MOD;
	}
	else{
		return (((tmp*tmp)%MOD)*x)%MOD;
	}
}
ll C(ll m,ll n){//m个里面选n个
	return (f[m]*((niyuan[n]*niyuan[m-n])%MOD))%MOD; 
}
int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin>>n>>m;
	for(int i=m;i>=1;i--){
		cin>>a[i];
	}
	f[0]=1;
	niyuan[0]=1;
	f[1]=1;
	niyuan[1]=1;
	for(int i=2;i<=n;i++){
		f[i]=(f[i-1]*i)%MOD;
		niyuan[i]=fastpow(f[i],MOD-2)%MOD;
	}
	a[0]=n+1;
	tn=0;
	ans=1;
	cnt=n/m-1;
	for(int i=1;i<=m;i++){	
		ans=(ans*C(a[i-1]-a[i]-1+tn,cnt))%MOD;
		tn=(tn+a[i-1]-a[i]-1-cnt);
	}
	cout<<ans<<endl;
	return 0;
}