#include <fstream>
using namespace std;

#define mod 1000003

int poz[100010], n, m;
long long sol = 1;

int main()
{
    int i, a;

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

    f >> n >> m;
    for(i = 1; i <= m; ++i)
    {
        f >> a;
        poz[a] = 1;
    }
    for(i = 1; i <= n; ++i)
        if(!poz[i])
            sol = (sol * 1LL * (i - 1)) % 1000003;

    g << sol << '\n';
    g.close();
    return 0;
}