#include<iostream>

using namespace std;

const int MOD=1000003;

int V[100005],N,M;

int main()
{
    int nr;
    
    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 ans=1;
    
    for(int i=2;i<=N;++i)
      if(!V[i])  ans=((long long)ans*(i-1))%MOD;
    
    printf("%d",ans);  
    
    return 0;
}