#include <cstdio>

const int MAX_N = 100000;
const int MOD = 1000003;

bool poz[1 + MAX_N];

int main() {
  freopen("grigo.in", "r", stdin);
  freopen("grigo.out", "w", stdout);
  
  int N, M;
  scanf("%d%d", &N, &M);
  for (int i = 1; i <= M; i++) {
    int x;
    scanf("%d", &x);
    poz[x] = true;
  }
  int ans = 1;
  for (int i = 1; i <= N; i++) {
    if (!poz[i]) {
      ans = 1LL * ((ans % MOD) * (i - 1) % MOD) % MOD;
    }
  }
  printf("%d\n", ans);
  return 0;
}