#include <iostream>
#include <fstream>
#define MOD 1000003
using namespace std;
ifstream f("grigo.in");
ofstream g("grigo.out");
int ok[100003];long long sol=1;
void solve()
{
    int n,m,i,x; f>>n>>m;
    for(i=1;i<=m;i++){f>>x; ok[x]=1;}
    for(i=2;i<=n;i++)if(ok[i]==0)sol=((i-1)*sol)%MOD;
    g<<sol;
}
int main()
{
    solve();
    return 0;
}