#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic warning "-Wunused-function"
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;
using mint = modint998244353;


constexpr int FACT_SIZE = 1000000;
mint Fact[FACT_SIZE + 1];
mint iFact[FACT_SIZE + 1];
const auto fact_init = [] {
    Fact[0] = mint::raw(1);
    for(int i = 1; i <= FACT_SIZE; ++i) {
        Fact[i] = Fact[i-1] * i;
    }
    iFact[FACT_SIZE] = Fact[FACT_SIZE].inv();
    for(int i = FACT_SIZE; i; --i) {
        iFact[i-1] = iFact[i] * i;
    }
    return false;
}();

mint comb(int n, int k) {
    if (k == 0) return mint::raw(1);
    assert(n >= 0 && k >= 0);
    if (k > n) return mint::raw(0);
    return Fact[n] * iFact[n - k] * iFact[k];
}

mint icomb(int n, int k) {
    return iFact[n] * Fact[n - k] * Fact[k];
}

mint fact(int n) {return Fact[n];}
mint perm(int n, int k) {
    assert(0 <= n);
    return Fact[n] * iFact[n - k];
}

vector<mint> fps_inv(vector<mint> f, int precision=-1) {
  if (precision == -1) precision = f.size();
  assert(precision >= 1 && f.size() >= 1 && f[0] != 0);
  auto f0 = f[0];
  if (f0 != 1) {
    f0 = f0.inv();
    for (auto& x : f) x *= f0;
  }
  int sz_tgt = bit_ceil(0U + precision);
  vector<mint> g(sz_tgt), g_ftt, fg;
  g_ftt.reserve(sz_tgt), fg.reserve(sz_tgt);
  g[0] = 1;
  static_assert(mint::mod() > 1 && (mint::mod() - 1) % 4 == 0);
  const mint i4 = mint::raw(mint::mod() - (mint::mod() - 1) / 4);
  mint iz = -1;
  for (int n = 1; n < sz_tgt; n *= 2) {
    fg.assign(f.begin(), f.begin() + min<int>(2 * n, f.size())), fg.resize(2 * n);
    g_ftt.assign(g.begin(), g.begin() + 2 * n);
    internal::butterfly(fg), internal::butterfly(g_ftt);
    for (int i = 0; i < 2 * n; i++) fg[i] *= g_ftt[i];
    internal::butterfly_inv(fg);
    for (int i = 0; i < n; i++) fg[i] = 0;
    internal::butterfly(fg);
    for (int i = 0; i < 2 * n; i++) fg[i] *= g_ftt[i];
    internal::butterfly_inv(fg);
    iz *= i4;
    for (int i = n; i < 2 * n; i++) g[i] = fg[i] * iz;
  }
  g.resize(precision);
  if (f0 != 1) for (auto& x : g) x *= f0;
  return g;
}

vector<mint> fps_log(vector<mint> f, int precision=-1) {
  if (precision == -1) precision = f.size();
  assert(precision >= 1 && f.size() >= 1 && f[0] == 1);
  auto f_inv = fps_inv(f, precision);
  for (int i = 0; i < ssize(f); i++) f[i] *= mint::raw(i);
  auto g = convolution(f, f_inv);
  g.resize(precision);
  for (int i = 1; i < precision; i++) g[i] *= iFact[i] * Fact[i-1];
  return g;
}

} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, m;
  cin >> n >> m;
  vector<char> a(n);
  rep(_, m) {
    int x;
    cin >> x;
    a[x-1] = true;
  }
  
  vector<mint> f(n);
  rep(i, n) f[i] = Fact[i+1];
  auto g = fps_log(f);
  rep(i, n) g[i] *= i;
  g[0] = 2;
  g.insert(g.begin(), 1, 0);
  vector<mint> dp[2];
  rep(i, 2) dp[i].resize(n);
  dp[0][0] = 1;
  auto dfs = [&](auto&& self, int l, int r) -> void {
    if (r - l == 1) {
      if (a[l]) swap(dp[0][l], dp[1][l]);
      return;
    }
    int c = (l + r) / 2;
    self(self, l, c);
    static vector<mint> ff, gg;
    gg.assign(g.begin(), g.begin() + r - l);
    rep(p, 2) {
      ff.assign(dp[p].begin() + l, dp[p].begin() + c);
      auto t = convolution(ff, gg);
      for (int i = c; i < r; i++) dp[p][i] += t[i - l];
    }
    self(self, c, r);
  };
  dfs(dfs, 0, n);
  cout << dp[0][n-1].val() << '\n';
}