#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#include <climits>
#include <cstring>
#include <cassert>


using namespace std;
//using namespace atcoder;

#define REP(i, n) for (int i=0; i<(n); ++i)
#define RREP(i, n) for (int i=(int)(n)-1; i>=0; --i)
#define FOR(i, a, n) for (int i=(a); i<(n); ++i)
#define RFOR(i, a, n) for (int i=(int)(n)-1; i>=(a); --i)

#define SZ(x) ((int)(x).size())
#define ALL(x) (x).begin(),(x).end()

#define DUMP(x) cerr<<#x<<" = "<<(x)<<endl
#define DEBUG(x) cerr<<#x<<" = "<<(x)<<" (L"<<__LINE__<<")"<<endl;

template<class T>
ostream &operator<<(ostream &os, const vector<T> &v) {
    os << "[";
    REP(i, SZ(v)) {
        if (i) os << ", ";
        os << v[i];
    }
    return os << "]";
}

template<class T, class U>
ostream &operator<<(ostream &os, const pair<T, U> &p) {
    return os << "(" << p.first << " " << p.second << ")";
}

template<class T>
bool chmax(T &a, const T &b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

template<class T>
bool chmin(T &a, const T &b) {
    if (b < a) {
        a = b;
        return true;
    }
    return false;
}

using ll = long long;
using ull = unsigned long long;
using ld = long double;
using P = pair<int, int>;
using vi = vector<int>;
using vll = vector<ll>;
using vvi = vector<vi>;
using vvll = vector<vll>;

const ll MOD = 1e9 + 7;
const int INF = INT_MAX / 2;
const ll LINF = LLONG_MAX / 2;
const ld eps = 1e-9;


// edit

template<ll mod = 998244353, ll primitive = 3>
struct NTT {

    /**
    * @brief 畳み込みの実行. O(nlog n)
    * @require n <= 2^23
    * @param[in] a, b: 畳み込みたい配列
    * @return 畳み込みした結果
    * @usage
    *   vector<ll> a(2*n+1), b(2*n+1);
    *   vector<ll> c = NTT<>::multiply(a, b);
    */
    static vector<ll> multiply(const vector<ll> &a, const vector<ll> &b) {
        auto A = NTT(a).solve();
        auto B = NTT(b).solve();

        vector<ll> C(A.size());
        REP(i, C.size()) C[i] = (A[i] * B[i]) % 998244353;

        return NTT(C).solve(true);
    }

private:
    int n;
    vector<ll> a;
    ll inv_n, root, inv_root;

    NTT(const vector<ll> &a) : n(1), a(a) {
        while (n < a.size()) n <<= 1;
        this->a.resize(n);
        inv_n = modpow(n, mod - 2);
        root = modpow(primitive, (mod - 1) / n);
        inv_root = modpow(root, mod - 2);
    }

    vector<ll> solve(bool inverse = false) {
        return ntt(0, 0, inverse, inverse ? inv_root : root);
    }

    vector<ll> ntt(int d, int bit, bool inverse, ll base) {
        int sz = n >> d;
        if (sz == 1) return {(a[bit] * (inverse ? inv_n : 1)) % mod};

        auto f0 = ntt(d + 1, bit, inverse, (base * base) % mod);
        auto f1 = ntt(d + 1, bit | 1 << d, inverse, (base * base) % mod);
        vector<ll> f(sz);
        ll tmp = 1;
        for (int i = 0; i < sz; ++i) {
            f[i] = (f0[i % (sz / 2)] + tmp * f1[i % (sz / 2)]) % mod;
            (tmp *= base) %= mod;
        }
        return f;
    }

    ll modpow(ll a, ll p) {
        ll ret = 1;
        while (p) {
            if (p & 1) (ret *= a) %= mod;
            (a *= a) %= mod;
            p >>= 1;
        }
        return ret;
    }
};

template<int64_t mod>
class modint {
public:
    int64_t x;

    modint(int64_t x = 0) : x(x < 0 ? ((x % mod) + mod) % mod : x % mod) {}

    const modint operator-() const { return x ? mod - x : 0; }

    modint &operator+=(const modint &rhs) {
        if ((x += rhs.x) >= mod) x -= mod;
        return *this;
    }

    modint &operator-=(const modint &rhs) {
        return *this += -rhs;
    }

    modint &operator*=(const modint &rhs) {
        (x *= rhs.x) %= mod;
        return *this;
    }

    modint &operator/=(const modint &rhs) {
        return *this *= rhs.pow(mod - 2);
    }

    friend const modint operator+(modint lhs, const modint &rhs) {
        return lhs += rhs;
    }

    friend const modint operator-(modint lhs, const modint &rhs) {
        return lhs -= rhs;
    }

    friend const modint operator*(modint lhs, const modint &rhs) {
        return lhs *= rhs;
    }

    friend const modint operator/(modint lhs, const modint &rhs) {
        return lhs /= rhs;
    }

    const modint pow(int64_t n) const {
        modint ret = 1, tmp = *this;
        while (n) {
            if (n & 1) ret *= tmp;
            tmp *= tmp;
            n >>= 1;
        }
        return ret;
    }

    friend bool operator==(const modint &lhs, const modint &rhs) {
        return lhs.x == rhs.x;
    }

    friend bool operator!=(const modint &lhs, const modint &rhs) {
        return !(lhs == rhs);
    }

    friend ostream &operator<<(ostream &os, const modint &a) {
        return os << a.x;
    }

    friend istream &operator>>(istream &is, modint &a) {
        int64_t tmp;
        is >> tmp;
        a = tmp;
        return is;
    }
};

using mint = modint<998244353>;
vector<mint> fact_v{1};
vector<mint> inv_p2_v{mint(1), mint(1) / mint(2)};
vector<mint> inv_fact_v;

mint fact(int x) {
    for (int i = SZ(fact_v); i <= x; ++i) {
        fact_v.push_back(fact_v.at(i - 1) * i);
    }
    return fact_v.at(x);
}

mint inv_p2(int p) {
    for (int i = SZ(inv_p2_v); i <= p; ++i) {
//        fact_v.push_back(fact_v.at(i - 1) * i);
        inv_p2_v.push_back(inv_p2_v.back() * inv_p2_v.at(1));
    }
    return inv_p2_v.at(p);
}

mint inv_fact(int x) {
    for (int i = SZ(inv_fact_v); i <= x; ++i) {
        inv_fact_v.push_back(mint(1) / fact(i));
    }
    return inv_fact_v[x];
}

void solve() {
    int N;
    cin >> N;
    int lim = 100000;

    vector<int> cnt(lim + 1);
    REP(i, 2 * N) {
        int tmp;
        cin >> tmp;
        cnt[tmp]++;
    }

    vector<vector<ll>> g; // g[i][j] = 身長A[i]がjペア違反する方法

    for (int i = 0; i <= lim; ++i) {
        if (cnt[i] == 0) continue;
        vector<ll> v;
        for (int j = 0; j * 2 <= cnt[i]; ++j) {
//            mint tmp = fact(cnt[i]) / (mint(2).pow(j) * fact(j) * fact(cnt[i] - 2 * j));
            mint tmp = fact(cnt[i]) * inv_p2(j) * inv_fact(j) * inv_fact(cnt[i] - 2 * j);
            v.push_back(tmp.x);
        }
        g.push_back(v);
    }

    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<>> pq;
    for (int i = 0; i < g.size(); ++i) {
        pq.push(make_pair((int) g[i].size(), i));
    }

    while (pq.size() > 1) {
        int i1 = pq.top().second;
        pq.pop();
        int i2 = pq.top().second;
        pq.pop();

        int s1 = g[i1].size();
        int s2 = g[i2].size();
//        int sn = s1 + s2 + 1;
        int sn = s1 + s2 + 1;
//        cerr << s1 << " " << s2 << " " << sn << endl;

        vector<ll> v1(sn), v2(sn);
        for (int i = 0; i < s1; ++i) {
            v1[i] = g[i1][i];
        }

        for (int i = 0; i < s2; ++i) {
            v2[i] = g[i2][i];
        }

        vector<ll> vn = NTT<>::multiply(v1, v2);
        vn.resize(sn);
        g[i1] = vn;
        pq.emplace(sn, i1);
    }

    auto f = g[pq.top().second];

    mint ans = 0;
    for (int i = 0; i <= N; ++i) {
        if (f.size() <= i) {
            break;
        }

        int sign = 1 - 2 * (i % 2);
//        mint tmp = mint(f[i]) * fact(2 * N - 2 * i) / (fact(N - i) * mint(2).pow(N - i));
        mint tmp = mint(f[i]) * fact(2 * N - 2 * i) * inv_fact(N - i) * inv_p2(N - i);
        ans += tmp * sign;
    }

    cout << ans << endl;


}


int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
//    std::ifstream in("input.txt");
//    std::cin.rdbuf(in.rdbuf());

    solve();


    return 0;
}


Measured memory_bytes: 49600