#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;

#define REP(i,n) for(ll i=0;i<(ll)n;i++)
#define dump(x)  cerr << "Line " << __LINE__ << ": " <<  #x << " = " << (x) << "\n";
#define spa << " " <<
#define fi first
#define se second
#define ALL(a)  (a).begin(),(a).end()
#define ALLR(a)  (a).rbegin(),(a).rend()

using ld = long double;
using ll = long long;
using ull = unsigned long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using pdd = pair<ld, ld>;

template<typename T> using V = vector<T>;
template<typename T> using P = pair<T, T>;
template<typename T> vector<T> make_vec(size_t n, T a) { return vector<T>(n, a); }
template<typename... Ts> auto make_vec(size_t n, Ts... ts) { return vector<decltype(make_vec(ts...))>(n, make_vec(ts...)); }
template<class S, class T> ostream& operator << (ostream& os, const pair<S, T> v){os << "(" << v.first << ", " << v.second << ")"; return os;}
template<typename T> ostream& operator<<(ostream &os, const vector<T> &v) { for (auto &e : v) os << e << ' '; return os; }
template<class T> ostream& operator<<(ostream& os, const vector<vector<T>> &v){ for(auto &e : v){os << e << "\n";} return os;}
struct fast_ios { fast_ios(){ cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_;

template <class T> void UNIQUE(vector<T> &x) {sort(ALL(x));x.erase(unique(ALL(x)), x.end());}
template<class T> bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; }
void fail() { cout << -1 << '\n'; exit(0); }
inline int popcount(const int x) { return __builtin_popcount(x); }
inline int popcount(const ll x) { return __builtin_popcountll(x); }
template<typename T> void debug(vector<vector<T>>&v,ll h,ll w){for(ll i=0;i<h;i++)
{cerr<<v[i][0];for(ll j=1;j<w;j++)cerr spa v[i][j];cerr<<"\n";}};
template<typename T> void debug(vector<T>&v,ll n){if(n!=0)cerr<<v[0];
for(ll i=1;i<n;i++)cerr spa v[i];
cerr<<"\n";};

const ll INF = (1ll<<62);
// const ld EPS   = 1e-10;
// const ld PI    = acos(-1.0);
// const ll mod = (int)1e9 + 7;
const ll mod = 998244353;

using mint = modint998244353;

int main(){

    // 二項係数
    const int n_max = 200000;
    std::vector<mint> fact(n_max);
    fact[0] = 1;
    for (int i = 1; i < n_max; ++i) {
        fact[i] = fact[i - 1] * i;
    }
    const auto comb = [&fact](int n, int r) {
        if(n<r or n<0 or r<0) return mint(0);
        return fact[n] / fact[r] / fact[n - r];
    };
    //

    ll N;
    cin >> N;
    V<ll> h(2*N);
    REP(i, 2*N){
        cin >> h[i];
    }

    map<ll, ll> mp;
    REP(i, 2*N){
        mp[h[i]]++;
    }
    V<ll> cnt;
    for(auto x: mp) cnt.push_back(x.second);
    ll sz = cnt.size();

    // dump(cnt)

    V<mint> tp(n_max);
    tp[0] = 1;
    REP(i, n_max-1) tp[i+1] = tp[i] * 2; 

    V<V<mint>> x(sz);

    REP(i, sz){
        REP(k, cnt[i]/2+1){
            mint res = 1;
            res *= comb(cnt[i], 2*k);
            res *= fact[2*k];
            res /= fact[k];
            res /= tp[k];
            x[i].push_back(res);
        }
    }

    // REP(i, sz){
    //     REP(j, x[i].size()) cout << x[i][j].val() << " ";
    //     cout << endl;
    // }

    queue<ll> qu;
    REP(i, sz) qu.push(i);    

    while((int)qu.size()>1){
        ll q1 = qu.front();qu.pop();
        ll q2 = qu.front();qu.pop();
        x[q1] = convolution(x[q1], x[q2]);
        qu.push(q1);
    }

    ll q = qu.front();
    auto v = x[q];

    sz = v.size();

    REP(k, sz){
        ll t = 2*N - 2*k;
        v[k] *= fact[t];
        v[k] /= fact[t/2];
        v[k] /= tp[t/2];
    }

    // for(auto x: v) cout << x.val() << " ";
    // cout << endl;

    mint res = 0;
    mint mo = mod-1;
    mint kei = 1;
    for(auto x: v){
        res += kei * x;
        kei *= mo;
    }

    cout << res.val() << endl;

    return 0;
}

Measured memory_bytes: 18996