#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
#define pi pair<ll, ll>
#define N 1111111
#define mod 1000000007
ll n, m, a[N], fac[N] = {1}, inv[N];
ll calc(int x, int y){
	//printf("c(%lld, %lld) = %lld\n", x, y, fac[x] * inv[y] % mod * inv[x - y] % mod);
	return fac[x] * inv[y] % mod * inv[x - y] % mod;
}
ll dfs(int x, int cnt){
	if(x == 0)
		return 1;
	return dfs(x - 1, cnt - (n / m) + (a[x] - a[x - 1])) * calc(cnt - 1, n / m - 1) % mod;
}
ll qpow(ll x, ll y){
    ll ans = 1, res = x % mod ;
    while(y){
        if(y & 1)
            ans = ans * res % mod;
        res = (res * res % mod);
        y >>= 1 ;
    }
    return ans ;
}
signed main()
{
    scanf("%lld%lld", &n, &m);
    for(int i = 1 ; i <= m ; i++)
    	scanf("%lld", &a[i]);
    sort(a + 1, a + 1 + m);
    for(int i = 1 ; i <= n ; i++)
    	fac[i] = fac[i - 1] * i % mod;
    inv[n] = qpow(fac[n], mod - 2);
    for(int i = n - 1 ; i >= 0 ; i--)
    	inv[i] = (i + 1) * inv[i + 1] % mod;
    sort(a + 1, a + 1 + m);
    printf("%lld", dfs(m, n - a[m] + 1));
    exit(0);
}