#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;
    long long 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,"%lld",s);

    return 0;
}