#include<cstdio>
using namespace std;

FILE *f=fopen("grigo.in","r");
FILE *g=fopen("grigo.out","w");

bool v[100001];
int main(){
	int x,n,m,i,s=1;
   
	fscanf (f,"%d%d",&n,&m);
    for(i=1;i<=m;++i){
		fscanf (f,"%d",&x);
		v[x]=1;
	}
    for(i=1;i<=n;++i){
		if(!v[i]){
			s=(s*(i-1))%1000003;
		}
	}
	fprintf (g,"%d",s);
 
    return 0;
}