#include <fstream>
#define mod 1000003
using namespace std;

ifstream f("grigo.in");
ofstream g("grigo.out");

int n, m, x;
long long sol=1;
bool v[100005];

int main()
{
    f>>n>>m;
    for (int i=1; i<=m; i++)
        f>>x, v[x]=1;

    for (int i=1; i<=n; i++)
        if (!v[i]) sol=(sol*(i-1))%mod;

    g<<sol<<'\n';

    return 0;
}