#include <cstdio>   
  
#define modulo 1000003   
#define Nmax 100001   
  
int N, M, i, p;   
char W[Nmax];   
  
int main()   
{   
 freopen("grigo.in","r",stdin);   
 scanf("%d %d",&N,&M);   
 for (i=1; i<=M; ++i)   
     {   
      scanf("%d",&p);   
      W[p] = 1;   
     }   
 for (i=1,p=1; i<=N; ++i)   
     if (!W[i]) p = ((long long)p*(i-1)) % modulo;   
 freopen("grigo.out","w",stdout);   
 printf("%d\n",p);   
 fclose(stdout);   
 return 0;   
}