#include<iostream>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<complex>
#include<bitset>
#include<stack>
#include<unordered_map>
#include<utility>
#include<tuple>
#include<cassert>
using namespace std;
typedef long long ll;
typedef unsigned int ui;
const ll mod = 998244353;
const ll INF = (ll)1000000007 * 1000000007;
typedef pair<int, int> P;
#define stop char nyaa;cin>>nyaa;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define Per(i,sta,n) for(int i=n-1;i>=sta;i--)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
typedef long double ld;
const ld eps = 1e-8;
const ld pi = acos(-1.0);
typedef pair<ll, ll> LP;
int dx[4]={1,-1,0,0};
int dy[4]={0,0,1,-1};
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(b<a){a=b;return 1;}return 0;}

template<int mod>
struct ModInt {
    long long x;
 
    ModInt() : x(0) {}
    ModInt(long long y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}

    explicit operator int() const {return x;}
 
    ModInt &operator+=(const ModInt &p) {
        if((x += p.x) >= mod) x -= mod;
        return *this;
    }
    ModInt &operator-=(const ModInt &p) {
        if((x += mod - p.x) >= mod) x -= mod;
        return *this;
    }
    ModInt &operator*=(const ModInt &p) {
        x = (int)(1LL * x * p.x % mod);
        return *this;
    }
    ModInt &operator/=(const ModInt &p) {
        *this *= p.inverse();
        return *this;
    }
 
    ModInt operator-() const { return ModInt(-x); }
    ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; }
    ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; }
    ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; }
    ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; }
 
    bool operator==(const ModInt &p) const { return x == p.x; }
    bool operator!=(const ModInt &p) const { return x != p.x; }
 
    ModInt inverse() const{
        int a = x, b = mod, u = 1, v = 0, t;
        while(b > 0) {
            t = a / b;
            a -= t * b;
            swap(a, b);
            u -= t * v;
            swap(u, v);
        }
        return ModInt(u);
    }

    ModInt power(long long p) const{
        int a = x;
        if (p==0) return 1;
        if (p==1) return ModInt(a);
        if (p%2==1) return (ModInt(a)*ModInt(a)).power(p/2)*ModInt(a);
        else return (ModInt(a)*ModInt(a)).power(p/2);
    }

    ModInt power(const ModInt p) const{
        return ((ModInt)x).power(p.x);
    }

    friend ostream &operator<<(ostream &os, const ModInt<mod> &p) {
        return os << p.x;
    }
    friend istream &operator>>(istream &is, ModInt<mod> &a) {
        long long x;
        is >> x;
        a = ModInt<mod>(x);
        return (is);
    }
};

using modint = ModInt<mod>;

struct ModFac{
  public:
    vector<modint> f,i_f;
    int n;

    ModFac(int n_){
      n=n_;
      f.resize(n+1,1);
      i_f.resize(n+1,1);
      for(int i=0;i<n;i++){
        f[i+1]=f[i]*(modint)(i+1);
      }
      i_f[n]=f[n].power(mod-2);
      for(int i=n-1;i>=0;i--){
        i_f[i]=i_f[i+1]*(modint)(i+1);
      }
    }
    ModFac(modint n_){
      n=(int)n_;
      f.resize(n+1,1);
      i_f.resize(n+1,1);
      for(int i=0;i<n;i++){
        f[i+1]=f[i]*(modint)(i+1);
      }
      i_f[n]=f[n].power(mod-2);
      for(int i=n-1;i>=0;i--){
        i_f[i]=i_f[i+1]*(modint)(i+1);
      }
    }
    
    modint factorial(int x){
      //cout << f.size() << endl;
      return f[x];
    }
        
    modint inv_factorial(int x){
      return i_f[x];
    }
    
    modint comb(int m,int k){
      if (m<0 or k<0) return 0;
      if (m<k) return 0;
      return f[m]*i_f[k]*i_f[m-k];
    }
};

constexpr int bmds(int x){
  const int v[] = {1012924417, 924844033, 998244353,
                   897581057, 645922817};
  return v[x];
}
constexpr int brts(int x){
  const int v[] = {5, 5, 3, 3, 3};
  return v[x];
}

template<int X>
struct NTT{
  static constexpr int md = bmds(X);
  static constexpr int rt = brts(X);
  using M = ModInt<md>;
  vector< vector<M> > rts,rrts;

  void ensure_base(int n){
    if((int)rts.size()>=n) return;
    rts.resize(n);rrts.resize(n);
    for(int i=1;i<n;i<<=1){
      if(!rts[i].empty()) continue;
      M w=M(rt).power((md-1)/(i<<1));
      M rw=w.inverse();
      rts[i].resize(i);rrts[i].resize(i);
      rts[i][0]=M(1);rrts[i][0]=M(1);
      for(int k=1;k<i;k++){
        rts[i][k]=rts[i][k-1]*w;
        rrts[i][k]=rrts[i][k-1]*rw;
      }
    }
  }

  void ntt(vector<M> &as,bool f){
    int n=as.size();
    assert((n&(n-1))==0);
    ensure_base(n);

    for(int i=0,j=1;j+1<n;j++){
      for(int k=n>>1;k>(i^=k);k>>=1);
      if(i>j) swap(as[i],as[j]);
    }

    for(int i=1;i<n;i<<=1){
      for(int j=0;j<n;j+=i*2){
        for(int k=0;k<i;k++){
          M z=as[i+j+k]*(f?rrts[i][k]:rts[i][k]);
          as[i+j+k]=as[j+k]-z;
          as[j+k]+=z;
        }
      }
    }

    if(f){
      M tmp=M(n).inverse();
      for(int i=0;i<n;i++) as[i]*=tmp;
    }
  }

  vector<M> multiply(vector<M> as,vector<M> bs){
    int need=as.size()+bs.size()-1;
    int sz=1;
    while(sz<need) sz<<=1;
    as.resize(sz,M(0));
    bs.resize(sz,M(0));

    ntt(as,0);ntt(bs,0);
    for(int i=0;i<sz;i++) as[i]*=bs[i];
    ntt(as,1);

    as.resize(need);
    return as;
  }

  vector<int> multiply(vector<int> as,vector<int> bs){
    vector<M> am(as.size()),bm(bs.size());
    for(int i=0;i<(int)am.size();i++) am[i]=M(as[i]);
    for(int i=0;i<(int)bm.size();i++) bm[i]=M(bs[i]);
    vector<M> cm=multiply(am,bm);
    vector<int> cs(cm.size());
    for(int i=0;i<(int)cs.size();i++) cs[i]=cm[i].x;
    return cs;
  }
};
template<int X> constexpr int NTT<X>::md;
template<int X> constexpr int NTT<X>::rt;

int M=100000;
int n;
int h[100010];
int z[100010];
vector<vector<modint>> f;
ModFac MF(200010);
modint v[100010];
NTT<2> ntt;

vector<modint> mul(int l,int r){
    if(r-l<1) return vector<modint>(1,1);
    if(r-l==1) return f[l];
    int mid=(l+r)/2;
    return ntt.multiply(mul(l,mid),mul(mid,r));
}

modint gr(int k,int j){
    return MF.comb(k,2*j)*v[2*j]*MF.inv_factorial(j);
}

void solve(){
    cin >> n;
    v[0]=1;
    rep(i,n){
        v[2*i+2]=v[2*i]*MF.comb(2*(i+1),2);
    }
    rep(i,2*n){
        cin >> h[i];h[i]--;
        z[h[i]]++;
    }
    f.resize(M);
    rep(i,M){
        f[i].resize(z[i]/2+1);
        rep(j,z[i]/2+1){
            f[i][j]=gr(z[i],j);
        }
    }
    sort(f.begin(),f.end(),[](vector<modint> &a,vector<modint> &b){return a.size()<b.size();});
    vector<modint> F=mul(0,M);
    F.resize(n+1);
    vector<modint> G(n+1);
    G[n]=F[n];
    per(i,n){
        G[i]=F[i]*v[2*n-2*i]*MF.comb(n,i)-(modint)(i+1)*G[i+1];
    }
    // rep(i,n+1){
    //     cout << i << " " << G[i] << " " << F[i] << endl;
    // }
    cout << G[0]*MF.inv_factorial(n) << endl;
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << fixed << setprecision(50);
    solve();
}

Measured memory_bytes: 19808