#include <cstdio>
#define Mod 1000003
using namespace std;

int n,m,i,x;
long long ans;
bool a[100004];

int main()
{
    freopen("grigo.in","r",stdin);
    freopen("grigo.out","w",stdout);

    scanf("%d%d",&n,&m);
    while(m--)
    {
        scanf("%d",&x);
        a[x]=1;
    }
    ans=1LL;

    for(i=1;i<=n;++i)
    if(!a[i]) ans=ans*(i-1)%Mod;

    printf("%lld\n",ans);
    return 0;
}