//#define NDEBUG

#pragma region cp_template

#include <algorithm>
#include <cstddef>
#include <cstdint>
#include <iostream>
#include <utility>
#include <vector>

namespace n91 {

  using i32 = std::int32_t;
  using i64 = std::int64_t;
  using u32 = std::uint32_t;
  using u64 = std::uint64_t;
  using isize = std::ptrdiff_t;
  using usize = std::size_t;

  struct rep {
    struct itr {
      usize i;
      constexpr itr(const usize i) noexcept : i(i) {}
      void operator++() noexcept { ++i; }
      constexpr usize operator*() const noexcept { return i; }
      constexpr bool operator!=(const itr x) const noexcept { return i != x.i; }
    };
    const itr f, l;
    constexpr rep(const usize f, const usize l) noexcept
      : f(std::min(f, l)), l(l) {}
    constexpr auto begin() const noexcept { return f; }
    constexpr auto end() const noexcept { return l; }
  };
  struct revrep {
    struct itr {
      usize i;
      constexpr itr(const usize i) noexcept : i(i) {}
      void operator++() noexcept { --i; }
      constexpr usize operator*() const noexcept { return i; }
      constexpr bool operator!=(const itr x) const noexcept { return i != x.i; }
    };
    const itr f, l;
    constexpr revrep(const usize f, const usize l) noexcept
      : f(l - 1), l(std::min(f, l) - 1) {}
    constexpr auto begin() const noexcept { return f; }
    constexpr auto end() const noexcept { return l; }
  };
  template <class T> auto md_vec(const usize n, const T& value) {
    return std::vector<T>(n, value);
  }
  template <class... Args> auto md_vec(const usize n, Args... args) {
    return std::vector<decltype(md_vec(args...))>(n, md_vec(args...));
  }
  template <class T> constexpr T difference(const T& a, const T& b) noexcept {
    return a < b ? b - a : a - b;
  }
  template <class T> void chmin(T& a, const T& b) noexcept {
    if (b < a)
      a = b;
  }
  template <class T> void chmax(T& a, const T& b) noexcept {
    if (a < b)
      a = b;
  }
  template <class F> class rec_lambda {
    F f;

  public:
    rec_lambda(F&& f) : f(std::move(f)) {}
    template <class... Args> auto operator()(Args&&... args) const {
      return f(*this, std::forward<Args>(args)...);
    }
  };
  template <class F> auto make_rec(F&& f) { return rec_lambda<F>(std::move(f)); }
  template <class T> T scan() {
    T ret;
    std::cin >> ret;
    return ret;
  }
  constexpr char eoln = '\n';
  template <class T> T ceildiv(const T& l, const T& r) {
    return l / r + (l % r != 0 ? 1 : 0);
  }

} // namespace n91

#pragma endregion cp_template

#include <cstdint>

template <std::uint_fast64_t mod> class modint {
  using u64 = std::uint_fast64_t;

public:
  u64 v;

  constexpr modint(const u64 x = 0) noexcept : v(x% mod) {}
  constexpr modint operator+(const modint rhs) const noexcept {
    return modint(*this) += rhs;
  }
  constexpr modint operator-(const modint rhs) const noexcept {
    return modint(*this) -= rhs;
  }
  constexpr modint operator*(const modint rhs) const noexcept {
    return modint(*this) *= rhs;
  }
  constexpr modint operator/(const modint rhs) const noexcept {
    return modint(*this) /= rhs;
  }
  constexpr modint& operator+=(const modint rhs) noexcept {
    v += rhs.v;
    if (v >= mod)
      v -= mod;
    return *this;
  }
  constexpr modint& operator-=(const modint rhs) noexcept {
    if (v < rhs.v)
      v += mod;
    v -= rhs.v;
    return *this;
  }
  constexpr modint& operator*=(const modint rhs) noexcept {
    v = v * rhs.v % mod;
    return *this;
  }
  constexpr modint& operator/=(modint rhs) noexcept {
    u64 exp = mod - 2;
    while (exp != 0) {
      if (exp % 2 != 0)
        *this *= rhs;
      rhs *= rhs;
      exp /= 2;
    }
    return *this;
  }
};

#include <queue>
#include <unordered_map>

#include <atcoder/convolution>

namespace n91 {

  void main_() {
    using mint = modint<998244353>;
    /*
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    //*/
    const usize n = scan<usize>();
    std::vector<usize> freq;
    {
      std::unordered_map<u32, usize> mp;
      for (const usize i : rep(0, 2 * n)) {
        ++mp[scan<u32>()];
      }
      for (const auto& e : mp) {
        freq.push_back(e.second);
        //std::cout << e.second << " ";
      }
      //std::cout << eoln;
    }
    std::vector<mint> fact(2 * n + 1);
    fact[0] = 1;
    for (const usize i : rep(0, 2 * n)) {
      fact[i + 1] = fact[i] * (i + 1);
    }
    std::vector<mint> pow2(n + 1);
    pow2[0] = 1;
    for (const usize i : rep(0, n)) {
      pow2[i + 1] = pow2[i] * 2;
    }
    using ull = unsigned long long;
    using poly = std::vector<ull>;
    std::vector<poly> ps;
    for (const usize e : freq) {
      poly p;
      for (usize i = 0; i * 2 <= e; ++i) {
        p.push_back((fact[e] / (fact[e - 2 * i] * fact[i] * pow2[i])).v);
      }
      ps.push_back(std::move(p));
    }
    const auto cmp = [](const poly& l, const poly& r) {
      return r.size() < l.size();
    };
    std::priority_queue<poly, std::vector<poly>, decltype(cmp)> que(
      cmp, std::move(ps));
    while (que.size() != 1) {
      auto px = que.top();
      que.pop();
      auto qx = que.top();
      que.pop();
      que.push(atcoder::convolution(std::move(px), std::move(qx)));
    }
    auto p = que.top();
    p.resize(n+1);
    //for(auto e : p)std::cout<<e<<" ";
    //std::cout<<eoln;
    mint ans = 0;
    mint c = 1;
    for (const usize i : rep(0, n + 1)) {
      ans += c * fact[2 * n - 2 * i] / (fact[n - i] * pow2[n - i]) * p[i];
      //std::cout << (fact[2 * n - 2 * i] / (fact[n - i] * pow2[n - i]) * p[i]).v << " ";
      c = mint(0) - c;
    }
    std::cout << ans.v << eoln;
  }

} // namespace n91

int main() {
  n91::main_();
  return 0;
}


Measured memory_bytes: 10452