#include<iostream>
#include<string>
#include<algorithm>
#include<vector>
#include<iomanip>
#include<math.h>
#include<complex>
#include<queue>
#include<deque>
#include<stack>
#include<map>
#include<set>
#include<bitset>
#include<functional>
#include<assert.h>
#include<numeric>
using namespace std;
#define REP(i,m,n) for(int i=(int)(m) ; i < (int) (n) ; ++i )
#define rep(i,n) REP(i,0,n)
using ll = long long;
constexpr int inf=1e9+7;
constexpr ll longinf=1LL<<60 ;
constexpr ll mod=998244353 ;

vector<ll> inv,fact,invfact;
void mod_build(int n=101010){
    fact.resize(n+1);
    inv.resize(n+1);
    invfact.resize(n+1);
    fact[0]=inv[0]=invfact[0]=1;
    inv[1]=1;
    rep(i,n){
        fact[i+1]=fact[i]*(i+1)%mod;
        if(i>0)inv[i+1]=mod-inv[mod%(i+1)]*(mod/(i+1))%mod;
        invfact[i+1]=invfact[i]*inv[i+1]%mod;
    }
}
ll perm(int n,int k){
    if(n<0||k<0||k>n)return 0;
    return fact[n]*invfact[n-k]%mod;
}
ll comb(int n,int k){
    if(n<0||k<0||k>n)return 0;
    return (fact[n]*invfact[n-k]%mod)*invfact[k]%mod;
}
ll powmod(ll n,ll k){
    k%=mod-1;
    if(k<0)k+=mod-1;
    ll ret=1;
    while(k){
        if(k&1)ret=ret*n%mod;
        n=n*n%mod;
        k>>=1;
    }
    return ret;
}

struct NumberTheoreticTransform
{
  int mod;
  int primitiveroot;

  NumberTheoreticTransform(int mod, int root) : mod(mod), primitiveroot(root) {}

  inline int mod_pow(int x, int n)
  {
    int ret = 1;
    while(n > 0) {
      if(n & 1) ret = mul(ret, x);
      x = mul(x, x);
      n >>= 1;
    }
    return ret;
  }

  inline int inverse(int x)
  {
    return (mod_pow(x, mod - 2));
  }

  inline int add(unsigned x, int y)
  {
    x += y;
    if(x >= mod) x -= mod;
    return (x);
  }

  inline int mul(int a, int b)
  {
    unsigned long long x = (long long) a * b;
    unsigned xh = (unsigned) (x >> 32), xl = (unsigned) x, d, m;
    asm("divl %4; \n\t" : "=a" (d), "=d" (m) : "d" (xh), "a" (xl), "r" (mod));
    return (m);
  }

  void DiscreteFourierTransform(vector< int > &F, bool rev)
  {
    const int N = (int) F.size();
    for(int i = 0, j = 1; j + 1 < N; j++) {
      for(int k = N >> 1; k > (i ^= k); k >>= 1);
      if(i > j) swap(F[i], F[j]);
    }
    int w, wn, s, t;
    for(int i = 1; i < N; i <<= 1) {
      w = mod_pow(primitiveroot, (mod - 1) / (i * 2));
      if(rev) w = inverse(w);
      for(int k = 0; k < i; k++) {
        wn = mod_pow(w, k);
        for(int j = 0; j < N; j += i * 2) {
          s = F[j + k], t = mul(F[j + k + i], wn);
          F[j + k] = add(s, t), F[j + k + i] = add(s, mod - t);
        }
      }
    }
    if(rev) {
      int temp = inverse(N);
      for(int i = 0; i < N; i++) F[i] = mul(F[i], temp);
    }
  }

  vector< int > Multiply(const vector< int > &A, const vector< int > &B)
  {
    int sz = 1;
    while(sz < A.size() + B.size() - 1) sz <<= 1;
    vector< int > F(sz), G(sz);
    for(int i = 0; i < A.size(); i++) F[i] = A[i];
    for(int i = 0; i < B.size(); i++) G[i] = B[i];
    DiscreteFourierTransform(F, false);
    DiscreteFourierTransform(G, false);
    for(int i = 0; i < sz; i++) F[i] = mul(F[i], G[i]);
    DiscreteFourierTransform(F, true);
    F.resize(A.size() + B.size() - 1);
    return (F);
  }
};

struct P{
    int x;
    vector<int> v;
    bool operator >(const P& rhs)const{
        return x > rhs.x;
    }
};
int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int n;
    cin>>n;
    vector<int> cnt(101010);
    rep(i,2*n){
        int x;
        cin>>x;
        cnt[x]++;
    }
    mod_build();
    priority_queue<P,vector<P>,greater<P>> pq;
    rep(i,101010){
        int m=cnt[i];
        if(m<2)continue;
        vector<int> a(m/2+1);
        ll ret = 1;
        rep(j,m/2+1){
            a[j]=ret;
            ret *= comb(m-2*j,2);
            ret %= mod;
            ret *= inv[j+1];
            ret%=mod;
        }
        pq.push({m,a});
    }
    pq.push({0,{1}});
    auto ntt = NumberTheoreticTransform(mod,3);
    while(pq.size()>1){
        auto p1 = pq.top();pq.pop();
        auto p2 = pq.top();pq.pop();
        auto res = ntt.Multiply(p1.v, p2.v);
        pq.push({(int)res.size(),res});
    }
    auto ret = pq.top().v;
    ll ans = 0;
    rep(i,ret.size()){
        int sz = 2*n-2*i;
        ll cnt = fact[sz] * invfact[sz/2] % mod * powmod(2,mod-1-sz/2) % mod;
        if(i%2)ans += mod - ret[i]*cnt % mod;
        else ans += ret[i]*cnt%mod;
    }
    cout<<ans%mod<<endl;
    return 0;
}

Measured memory_bytes: 8044