#include <algorithm>
#include <cassert>
#include <cctype>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstring>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <vector>
#include <list>
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#ifdef DEBUG
#define show(...) cerr << #__VA_ARGS__ << " = ", debug(__VA_ARGS__);
#else
#define show(...) 42
#endif
using namespace std;
using ll = long long;
using pii = pair<int, int>;
template <typename T, typename S>
ostream& operator<<(ostream& os, pair<T, S> a) {
    os << '(' << a.first << ',' << a.second << ')';
    return os;
}
template <typename T>
ostream& operator<<(ostream& os, vector<T> v) {
    for (auto x : v) os << x << ' ';
    return os;
}
void debug() {
    cerr << '\n';
}
template <typename H, typename... T>
void debug(H a, T... b) {
    cerr << a;
    if (sizeof...(b)) cerr << ", ";
    debug(b...);
}

//負の数を掛けたりするとバグる
template<int MOD>
class Modint{
public:
    int a;
    Modint(const long long v = 0):a(v % MOD){}
    static constexpr int getmod(){
        return MOD;
    }
    Modint operator+(const Modint rhs) const{
        return Modint(*this) += rhs;
    }
    Modint operator-(const Modint rhs) const{
        return Modint(*this) -= rhs;
    }
    Modint operator*(const Modint rhs) const{
        return Modint(*this) *= rhs;
    }
    Modint operator/(const Modint rhs) const{
        return Modint(*this) /= rhs;
    }
    Modint operator+(const long long rhs) const{
        return Modint(*this) += rhs;
    }
    Modint operator-(const long long rhs) const{
        return Modint(*this) -= rhs;
    }
    Modint operator*(const long long rhs) const{
        return Modint(*this) *= rhs;
    }
    Modint operator/(const long long rhs) const{
        return Modint(*this) /= rhs;
    }
    friend Modint operator+(const long long a, const Modint b){
        return b + a;
    }
    friend Modint operator-(const long long a, const Modint b){
        return -b + a;
    }
    friend Modint operator*(const long long a, const Modint b){
        return b * a;
    }
    friend Modint operator/(const long long a, const Modint b){
        return Modint(a) / b;
    }
    Modint &operator+=(const Modint rhs){
        a += rhs.a;
        if(a >= MOD){
            a -= MOD;
        }
        return *this;
    }
    Modint &operator-=(const Modint rhs){
        if(a < rhs.a){
            a += MOD;
        }
        a -= rhs.a;
        return *this;
    }
    Modint &operator*=(const Modint rhs){
        a = (long long)a * rhs.a % MOD;
        return *this;
    }
    Modint &operator/=(Modint rhs){
        int x = MOD - 2;
        while(x){
            if(x % 2){
                *this *= rhs;
            }
            rhs *= rhs;
            x /= 2;
        }
        return *this;
    }
    Modint &operator++(){
        *this += 1;
        return *this;
    }
    Modint &operator--(){
        *this -= 1;
        return *this;
    }
    Modint operator++(int){
        Modint res = *this;
        ++(*this);
        return res;
    }
    Modint operator--(int){
        Modint res = *this;
        --(*this);
        return res;
    }
    Modint &operator+=(const long long rhs){
        *this += Modint(rhs);
        return *this;
    }
    Modint &operator-=(const long long rhs){
        *this -= Modint(rhs);
        return *this;
    }
    Modint &operator*=(const long long rhs){
        *this *= Modint(rhs);
        return *this;
    }
    Modint &operator/=(const long long rhs){
        *this /= Modint(rhs);
        return *this;
    }
    Modint operator+() const{
        return *this;
    }
    Modint operator-() const{
        return Modint()-*this;
    }
    bool operator==(const Modint rhs) const{
        return a == rhs.a;
    }
    bool operator==(const long long rhs) const{
        return a == rhs;
    }
    friend bool operator==(const long long a, const Modint b){
        return a == b.a;
    }
    bool operator!=(const Modint rhs) const{
        return a != rhs.a;
    }
    bool operator!=(const long long rhs) const{
        return a != rhs;
    }
    friend ostream &operator<<(ostream &os, const Modint x){
        os << x.a;
        return os;
    }
    friend istream &operator>>(istream &is, Modint &x){
        is >> x.a;
        return is;
    }
    explicit operator bool() const{
        return a > 0;
    }
    bool operator!(){
        return a == 0;
    }
    explicit operator int() const{
        return a;
    }
    explicit operator long long() const{
        return (long long) a;
    }
    friend Modint pow(Modint a, long long b){
        Modint res = 1;
        while(b){
            if(b % 2){
                res *= a;
            }
            a *= a;
            b /= 2;
        }
        return res;
    }
};
using mint = Modint<998244353>;
const int NUM = 400005;
mint fact[NUM + 1], fact_inv[NUM + 1], inv[NUM + 1];
mint combi(long long N_, long long K_){
    static const int Mod_ = fact[0].getmod();
    static_assert(NUM < Mod_, "");
    if(fact[0] == 0){
        inv[1] = fact[0] = fact_inv[0] = 1;
        for(int i = 2; i <= NUM; i++){
            inv[i] = inv[Mod_ % i] * (Mod_ - Mod_ / i);
        }
        for(int i = 1; i <= NUM; i++){
            fact[i] = fact[i - 1] * i;
            fact_inv[i] = fact_inv[i - 1] * inv[i];
        }
    }
    if(K_ < 0 or K_ > N_) return 0;
    return fact_inv[K_] * fact[N_] * fact_inv[N_ - K_];
}
mint hcomb(long long N_, long long K_){
    return ((N_ | K_) == 0) ? 1 : combi(N_ + K_ - 1, K_);
}
#define MOD 998244353
#define root 3
 
unsigned int add(const unsigned int x, const unsigned int y)
{
    return (x + y < MOD) ? x + y : x + y - MOD;
}
 
unsigned int sub(const unsigned int x, const unsigned int y)
{
    return (x >= y) ? (x - y) : (MOD - y + x);
}
 
unsigned int mul(const unsigned int x, const unsigned int y)
{
    return (unsigned long long)x * y % MOD;
}
 
unsigned int mod_pow(unsigned int x, unsigned int n)
{
    unsigned int res = 1;
    while(n > 0){
        if(n & 1){ res = mul(res, x); }
        x = mul(x, x);
        n >>= 1;
    }
    return res;
}
 
unsigned int inverse(const unsigned int x)
{
    return mod_pow(x, MOD - 2);
}
 
void ntt(vector<int>& a, const bool rev = false)
{
    unsigned int i, j, k, l, p, q, r, s;
    const unsigned int size = a.size();
    if(size == 1) return;
    vector<int> b(size);
    r = rev ? (MOD - 1 - (MOD - 1) / size) : (MOD - 1) / size;
    s = mod_pow(root, r);
    vector<unsigned int> kp(size / 2 + 1, 1);
    for(i = 0; i < size / 2; ++i) kp[i + 1] = mul(kp[i], s);
    for(i = 1, l = size / 2; i < size; i <<= 1, l >>= 1){
        for(j = 0, r = 0; j < l; ++j, r += i){
            for(k = 0, s = kp[i * j]; k < i; ++k){
                p = a[k + r], q = a[k + r + size / 2];
                b[k + 2 * r] = add(p, q);
                b[k + 2 * r + i] = mul(sub(p, q), s);
            }
        }
        swap(a, b);
    }
    if(rev){
        s = inverse(size);
        for(i = 0; i < size; i++){ a[i] = mul(a[i], s); }
    }
}
 
vector<int> convolute(const vector<int>& a, const vector<int>& b)
{
    const int size = (int)a.size() + (int)b.size() - 1;
    int t = 1;
    while(t < size){ t <<= 1; }
    vector<int> A(t, 0), B(t, 0);
    for(int i = 0; i < (int)a.size(); i++){ A[i] = a[i]; }
    for(int i = 0; i < (int)b.size(); i++){ B[i] = b[i]; }
    ntt(A), ntt(B);
    for (int i = 0; i < t; i++){ A[i] = mul(A[i], B[i]); }
    ntt(A, true);
    A.resize(size);
    return A;
}
int cnt[200005];
mint inv2[200005];
int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int n;
    cin >> n;
//    n = 50000;
    vector<int>h(2*n);
    rep(i,2*n){
        h[i] = rand()%(2*n);
        cin >> h[i];
        cnt[h[i]]++;
    }
    vector<int>a;
    rep(i,200005)if(cnt[i])a.push_back(cnt[i]);
    sort(a.begin(), a.end());
    vector<vector<int>> dp;
    inv2[200004] = mint(1)/pow(mint(2),200004);
    for(int i = 200003; i >= 0; i--)inv2[i] = inv2[i+1] * 2;
    vector<int>q;
    for(int x: a){
        vector<int>dp2;
        for(int i = 0; i <=x/2; i++){
            //iペア作る
            mint k =combi(x,2*i)*fact[2*i]*fact_inv[i]*inv2[i];
            dp2.push_back(k.a);
        }
        dp.push_back(dp2);
        q.push_back((int)dp.size()-1);
    }
    while(q.size()>1){
        vector<int>qq;
        rep(i,q.size()/2){
            dp[q[i*2]] = convolute(dp[q[i*2]], dp[q[i*2+1]]);
            qq.push_back(q[i*2]);
        }
        if(q.size()&1)qq.push_back(q.back());
        q = qq;
    }
    mint ans = 0;
    auto dp2 = dp[q.front()];
    dp2.resize(n + 1);
    rep(i,n+1){
        mint k = fact[2*n-2*i]*fact_inv[n-i]*inv2[n-i] * dp2[i];
        if(i&1)ans -=k;
        else ans += k;
    }
    cout << ans << endl;
}


Measured memory_bytes: 16460