#include <bits/stdc++.h>
#define ll long long
#define ull unsigned long long 
#define ld long double
#define pii pair<int, int>
#define pll pair<ll, ll>
#define pb push_back
#define eb emplace_back

using namespace std;

const int mod = 1e6 + 3;

signed main()
{
    #ifndef TEST 
        freopen("grigo.in", "r", stdin);
        freopen("grigo.out", "w", stdout);
    #endif
    ios_base :: sync_with_stdio(false);
    cin.tie(nullptr), cout.tie(nullptr);
    
    int n, m;
    cin >> n >> m;
    vector<bool> ok(n + 1, false);
    for (int i = 1; i <= m; i++)
    {
        int x;
        cin >> x;
        ok[x] = true;
    }
    int ans = 1;
    for (int i = 1; i <= n; i++)
    {
        if (!ok[i])
        {
            ans = 1ll * ans * (i - 1) % mod;
        }
    }
    cout << ans;
    return 0;
}