#include <bits/stdc++.h>

#if MYDEBUG
#include "lib/cp_debug.hpp"
#else
#define DBG(...) ;
#endif
#if __cplusplus <= 201402L
template <typename T>
T gcd(T a, T b) { return ((a % b == 0) ? b : gcd(b, a % b)); }
template <typename T>
T lcm(T a, T b) { return a / gcd(a, b) * b; }
#endif
using LL = long long;
constexpr LL LINF = 334ll << 53;
constexpr int INF = 15 << 26;
constexpr LL MOD = 998244353;

namespace Problem {
using namespace std;
template <long long Mod = MOD>
class Modint {
 public:
  long long v;

  Modint(const Modint &x) { v = x.v; }
  explicit Modint(int x) {
    if (x < 0 or Mod <= x) x %= Mod;
    if (x < 0) x += Mod;
    v = x;
  }
  explicit Modint(long long x) {
    if (x < 0 or Mod <= x) x %= Mod;
    if (x < 0) x += Mod;
    v = x;
  }
  explicit Modint(unsigned x) {
    if (Mod <= x) x %= Mod;
    v = x;
  }
  explicit Modint(unsigned long long x) {
    if (Mod <= x) x %= Mod;
    v = x;
  }
  template <typename T>
  explicit Modint(T x) {
    if (x < 0 or Mod <= x) x %= Mod;
    v = x;
  }
  Modint() : v(0) {}
  long long get() const { return v; }
  Modint mpow(Modint &n) const { return mpow(n.v); }
  Modint mpow(long long n) const {
    long long i = 1, p = v;
    Modint ret(1);
    while (i <= n) {
      if (i & n) ret *= p;
      i = (i << 1);
      p = (p * p) % Mod;
    }
    return ret;
  }
  Modint operator-() const { return (v ? Modint(Mod - v) : Modint(0)); }
  explicit operator int() const { return v; }
  explicit operator long long() const { return v; }
  Modint &operator+=(const Modint &a) {
    v = (v + a.v);
    if (v >= Mod) v -= Mod;
    return *this;
  }
  Modint &operator-=(const Modint &a) {
    v = (v - a.v);
    if (v < 0) v += Mod;
    return *this;
  }
  Modint &operator*=(const Modint &a) {
    v = (v * a.v) % Mod;
    return *this;
  }
  Modint &operator/=(const Modint &a) {
    v = (v * a.mpow(Mod - 2).v) % Mod;
    return *this;
  }
  template <class T>
  Modint &operator+=(const T &a) {
    v = (v + Modint(a).v);
    if (v >= Mod) v -= Mod;
    return *this;
  }
  template <class T>
  Modint &operator-=(const T &a) {
    v = (v - Modint(a).v);
    if (v < 0) v += Mod;
    return *this;
  }
  template <class T>
  Modint &operator*=(const T &a) {
    v = (v * Modint(a).v) % Mod;
    return *this;
  }
  template <class T>
  Modint &operator/=(const T &a) {
    v = (v * Modint(a).mpow(Mod - 2).v) % Mod;
    return *this;
  }
  friend Modint operator+(const Modint &a, const Modint &b) {
    return Modint(a) += b;
  }
  friend Modint operator-(const Modint &a, const Modint &b) {
    return Modint(a) -= b;
  }
  friend Modint operator*(const Modint &a, const Modint &b) {
    return Modint(a) *= b;
  }
  friend Modint operator/(const Modint &a, const Modint &b) {
    return Modint(a) /= b;
  }
  template <class T, class U>
  friend Modint operator+(const T &a, const U &b) {
    return Modint(a) += Modint(b);
  }
  template <class T, class U>
  friend Modint operator-(const T &a, const U &b) {
    return Modint(a) -= Modint(b);
  }
  template <class T, class U>
  friend Modint operator*(const T &a, const U &b) {
    return Modint(a) *= Modint(b);
  }
  template <class T, class U>
  friend Modint operator/(const T &a, const U &b) {
    return Modint(a) /= Modint(b);
  }
};

template <long long M>
ostream &operator<<(ostream &os, const Modint<M> m) {
  return os << m.v;
}
class Solver {
 public:
  int n;
  vector<int> d;
  Solver(LL n) : n(n), d(n){};

  void solve() {
    int maxd = 0;
    vector<int> cnt(100001);
    for (int i = 0; i < n; ++i) {
      cin >> d[i];
      maxd = max(maxd, d[i]);
      if (i != 0 && d[i] == 0) {
        cout << 0 << endl;
        return;
      }
      cnt[d[i]]++;
    }
    if (d[0] != 0) {
      cout << 0 << endl;
      return;
    }
    for (int i = 0; i <= maxd; ++i) {
      if (cnt[i] == 0) {
        cout << 0 << endl;
        return;
      }
    }
    Modint<> ans(1);
    for (int i = 1; i <= maxd; ++i) {
      ans *= Modint<>(cnt[i - 1]).mpow(cnt[i]);
    }
    cout << ans << endl;
  }
};

}  // namespace Problem

int main() {
  std::cin.tie(0);
  std::ios_base::sync_with_stdio(false);
  // std::cout << std::fixed << std::setprecision(12);
  long long n = 0;
  std::cin >> n;

  Problem::Solver sol(n);
  sol.solve();
  return 0;
}


Measured memory_bytes: 1024