#include<cstdio>
#define max_n 1000
#define MOD 1000003
using namespace std;
int i, n, x, m;
bool fix[max_n];
long long nr=1;
int main(){
    freopen("grigo.in","r",stdin);
    freopen("grigo.out","w",stdout);
    scanf("%d%d", &n, &m);
    for (i=1;i<=m;i++) {scanf("%d", &x); fix[x]=true;}
    for (i=2;i<=n;i++) if (!fix[i]) nr=(nr*(i-1))%MOD;
    printf("%d\n", nr); return 0;
}