#include<stdio.h>
long long vizibil[100005],j,i,n,m,M=1000003,sol=1,poz;
int main()
{
        freopen("grigo.in","r",stdin);
        freopen("grigo.out","w",stdout);
        scanf("%lld%lld",&n,&m);
        for(i=1;i<=m;i++)
        { scanf("%lld",&poz);vizibil[poz]=1;}
        for(i=1;i<=n;i++)
        { if(vizibil[i])continue;
          sol*=(i-1);sol%=M;
        }
        printf("%lld",sol);
        return 0;
}