#include<fstream>

using namespace std;

#define MOD 1000003;
#define Nmax 100005

int V[Nmax],N,M,nr;

int main()
{
    freopen("grigo.in","r",stdin);
    freopen("grigo.out","w",stdout);

    scanf("%d %d",&N,&M);

    for(int i=1;i<=M;++i)
		scanf("%d",&nr),V[nr]=1;

    int sol=1;

    for(int i=2;i<=N;++i)
		if (!V[i])  
			sol=((long long)sol*(i-1))%MOD;

    printf("%d",sol);

    return 0;
}