#include <bits/stdc++.h>
#define int long long
using namespace std;
int n,m;
bool v[1000005];
signed main()
{
    ifstream cin("grigo.in");
    ofstream cout("grigo.out");
    cin>>n>>m;
    int rez=1;
    for(int i=1; i<=m; i++)
    {
        int a;
        cin>>a;
        v[a]=true;
    }
    for(int i=1;i<=n;i++)
    {
        if(v[i]==false)
        {
            rez=rez*(i-1)%1000003;
        }
    }
    cout<<rez;

        return 0;
}