#include <fstream>

using namespace std;
ifstream in("grigo.in");
ofstream out("grigo.out");
bool v[100001];
int main()
{
    long long n,m,i,c1=1,nr;
    in>>n>>m;
    for(i=1;i<=m;++i)
        {in>>nr,v[nr-1]=1;}
    for(i=1;i<n;++i)
        if(v[i]==0)c1=(long long)(c1*i)%1000003;
    out<<c1;
    return 0;
}