#include <fstream>

using namespace std;
ifstream fin("grigo.in");
ofstream fout("grigo.out");
bool v[100001];
int main()
{
    long long i,x,n,sum = 1,m;
    fin >> n >> m;
    for(i=1;i<=m;i++){
        fin >> x;
        v[x-1] = true;
    }
    for(i=1;i<n;i++){
        if(!v[i])
            sum = sum*i % 1000003;
    }
    fout << sum;
    return 0;
}