#include <iostream>
#include <vector>
#include <queue>
#include <algorithm>
#include <map>
#include <set>
#include <unistd.h>
#include <stdlib.h>
#include <atcoder/convolution>

using namespace std;
using namespace atcoder;

// using mint = long double;
// using mint = modint998244353;
// using mint = modint1000000007;

typedef long long ll;
typedef pair<ll, ll> P;
typedef pair<P, ll> T;
typedef pair<ll, vector<ll>> Pd;

const ll INF = 2e18;
const ll fact_table = 3200008;

priority_queue <ll> pql;
priority_queue <P> pqp;
//big priority queue
priority_queue <ll, vector<ll>, greater<ll> > pqls;
priority_queue <P, vector<P>, greater<P> > pqps;
//small priority queue
//top pop

ll dx[8] = {1, 0, -1, 0, 1, 1, -1, -1};
ll dy[8] = {0, 1, 0, -1, 1, -1, -1, 1};
//↓,→,↑,←

/*
#define endl "\n"
#ifdef ENJAPMA
#undef endl
#endif
*/

#define p(x) cout<<x<<endl;
#define el cout<<endl;
#define pe(x) cout<<x<<" ";
#define ps(x) cout<<fixed<<setprecision(25)<<x<<endl;
#define pu(x) cout<<(x);
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define CLEAR(a) a = decltype(a)();
#define pc(x) cout << x << ",";
#define rep(i, n) for (ll i = 0; i < (n); i ++)

typedef vector<ll> vec;
typedef vector<vector<ll>> mat;

const ll mod = 998244353ll;
// const ll mod = 1000000007ll;

ll mypow(ll a, ll b, ll m = mod) {ll x = 1; while (b) {while (!(b & 1)) {(a *= a) %= m; b >>= 1;}(x *= a) %= m; b--;} return x;}
vec readvec(ll read) { vec res(read); for (int i = 0; i < read; i++) { cin >> res[i]; } return res;}
void YES(bool cond) { if (cond) { p("YES");} else { p("NO");} return;}
void Yes(bool cond) { if (cond) { p("Yes");} else { p("No");} return;}
void line() { p("--------------------"); return;}


ll fact[fact_table + 5], rfact[fact_table + 5];

void c3_init() {
    fact[0] = rfact[0] = 1;
    for (ll i = 1; i <= fact_table; i++) {
        fact[i] = (fact[i - 1] * i) % mod;
    }
    rfact[fact_table] = mypow(fact[fact_table], mod - 2, mod);
    for (ll i = fact_table; i >= 1; i--) {
        rfact[i - 1] = rfact[i] * i;
        rfact[i - 1] %= mod;
    }
    return;
}
ll c3(ll n, ll r) {
    return (((fact[n] * rfact[r]) % mod ) * rfact[n - r]) % mod;
}


bool multicase = false;

ll cnt[100005], dp[100005];

ll c2table[100005], rc2table[100005];

ll makepair(ll size, ll num) {
    ll res1 = c2table[size];
    ll res2 = rc2table[size - num * 2];
    ll res = (res1 * res2) % mod;
    res *= rfact[num];
    res %= mod;
    return res;
}

void pre_calc() {
    c2table[1] = c2table[0] = 1;
    c2table[2] = 1, c2table[3] = 3;
    for (int i = 4; i <= 100000; i++) {
        c2table[i] = c2table[i - 2] * c3(i, 2);
        c2table[i] %= mod;
    }
    rc2table[100000] = mypow(c2table[100000], mod - 2, mod);
    rc2table[99999] = mypow(c2table[99999], mod - 2, mod);
    for (int i = 99998; i >= 0; i--) {
        rc2table[i] = rc2table[i + 2] * c3(i + 2, 2);
        rc2table[i] %= mod;
        assert(c2table[i] == mypow(rc2table[i], mod - 2, mod));
    }
    return;
}


void solve() {
    ll n;
    cin >> n;
    c3_init();
    pre_calc();
    for (int i = 0; i < 2 * n; i++) {
        ll val;
        cin >> val;
        cnt[val] ++;
    }
    dp[0] = 1;
    multiset<Pd> st;
    for (int i = 1; i <= 100000; i++) {
        ll size = cnt[i];
        if (size <= 1) continue;

        vec v = {1};

        for (int k = 1; k * 2ll <= size; k++) {
            ll p = makepair(size, k);
            v.pb(p);
        }

        ll len = v.size();

        st.insert({len, v});
    }

    st.insert({1ll, {1ll}});

    while (st.size() > 1) {
        Pd res1 = *st.begin();
        st.erase(st.begin());
        Pd res2 = *st.begin();
        st.erase(st.begin());

        vec r1 = res1.second, r2 = res2.second;

        vec c = atcoder::convolution(r1, r2);
        st.insert({res1.first + res2.first - 1, c});
    }

    vec finaldp = (*st.begin()).second;

    for (int i = 0; i <= n; i++) {
        if (i + 1 > finaldp.size()) {
            dp[i] = 0;
        } else {
            dp[i] = finaldp[i];
        }
    }

    ll value = 1ll, s = 2ll * n;
    ll chose = n;
    for (int i = 0; i <= n; i++) {
        dp[i] *= ((value * c2table[s]) % mod);
        dp[i] %= mod;

        value *= chose; 
        chose --;

        value %= mod;

        s -= 2;
    }
    ll sign = 1ll, ans = 0;
    for (int i = 0; i <= n; i++) {
        ans += (sign * dp[i] + mod);
        ans %= mod;
        sign *= -1;
    }
    ans *= mypow(fact[n], mod - 2, mod);
    ans %= mod;
    p(ans);
    return;
}


int main() {
    // init();
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    ll q, testcase = 1;
    if (multicase) {
        cin >> q;
    } else {
        q = 1;
    }
    while (q--) {
        // pu("Case ");pu("#");pu(testcase);pu(": ");
        solve();
        testcase++;
    }

    // solve();
    return 0;
}

Measured memory_bytes: 59464