#include <iostream>
#include <fstream>

using namespace std;

int n, m;
bool visible[100010];
int sol;

int main()
{
    ifstream f ("grigo.in");
    f>>n>>m;
    int i, x;
    for (i=1; i<=m; i++)
    {
        f>>x;
        visible[x] = true;
    }
    f.close();
    sol = 1;

    for (i=1; i<=n; i++)
        if (!visible[i])
            sol = (1LL*sol*(i-1))%1000003;

    ofstream g("grigo.out");
    g<<sol<<"\n";
    g.close();


    return 0;
}