#include <iostream>
#include <fstream>

using namespace std;

ifstream f ("grigo.in");
ofstream g ("grigo.out");

const int MOD = 1000003, MMAX = 100000 + 1;
int n, m;
int vizibil[MMAX];

long long solutie (int x) {
    long long sol = 1;
    for (int i = 2; i <= n; i++)
        if (!vizibil[i]) sol = sol * (i - 1) % MOD;
    return sol;
}

void citeste () {
    f >> n >> m;
    int x;
    for (int i = 1; i <= m; i++) f >> x, vizibil[x] = 1;
}

int main () {
    citeste();
    if (vizibil[1] == 0) g << 0 << '\n';
    else g << solutie(1) << '\n';
    return 0;
}