#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef pair<ll, ll> p_ll;

template<class T>
void debug(T itr1, T itr2) { auto now = itr1; while(now<itr2) { cout << *now << " "; now++; } cout << endl; }
#define repr(i,from,to) for (ll i=(ll)from; i<(ll)to; i++)
#define all(vec) vec.begin(), vec.end()
#define rep(i,N) repr(i,0,N)
#define per(i,N) for (ll i=(ll)N-1; i>=0; i--)

const ll MOD = 998244353;
const ll LLINF = pow(2,61)-1;
const ll INF = pow(2,30)-1;

vector<ll> fac;
void c_fac(ll x=pow(10,6)+10) { fac.resize(x,true); rep(i,x) fac[i] = i ? (fac[i-1]*i)%MOD : 1; }
ll inv(ll a, ll m=MOD) { ll b = m, x = 1, y = 0; while (b!=0) { ll d = a/b; a -= b*d; swap(a,b); x -= y*d; swap(x,y); } return (x+m)%m; }
ll nck(ll n, ll k) { return fac[n]*inv(fac[k]*fac[n-k]%MOD)%MOD; }
ll modpow(ll x, ll p) { ll result = 1, now = 1, pm = x; while (now<=p) { if (p&now) { result = result * pm % MOD; } now*=2; pm = pm*pm % MOD; } return result; }
ll gcd(ll a, ll b) { if (a<b) swap(a,b); return b==0 ? a : gcd(b, a%b); }
ll lcm(ll a, ll b) { return a/gcd(a,b)*b; }

// ----------------------------------------------------------------------
// ----------------------------------------------------------------------

struct FastNumberTheoreticTransform {

  ll size = 1, size_x12, root;
  vector<ll> x1, x2, theta;

  FastNumberTheoreticTransform(ll s=10) { 
    while(size<s) size*=2;
    root = modpow(3,MOD/size);
    x1.resize(size); x2.resize(size); theta.resize(size);
    rep(i,size) theta[i] = i==0 ? 1 : theta[i-1]*root % MOD;
  }

  void set(vector<ll> &v1, vector<ll> &v2) { 
    size_x12 = v1.size() + v2.size() - 1;
    x1 = v1; x2 = v2;
  }

  vector<ll> convolution(vector<ll> &x, bool rev, ll s, ll pos=0) {
    if (s==1) return {x[pos]};
    vector<ll> ex = convolution(x,rev,s/2,pos), ox = convolution(x,rev,s/2,pos+size/s);
    vector<ll> result(s);
    rep(i,s) result[i] = (ex[i%(s/2)] + theta[size/s*i] * ox[i%(s/2)]) % MOD;
    if (rev && s==size) {
      reverse(result.begin()+1, result.end());
      ll invs = inv(size);
      for (auto &x: result) x = x * invs % MOD;
    }
    return result;
  };

  vector<ll> calc(vector<ll> &v1, vector<ll> &v2) {
    set(v1,v2);
    vector<ll> cx1 = convolution(x1, false, size), cx2 = convolution(x2, false, size);
    vector<ll> cx12(size); rep(i,size) cx12[i] = cx1[i] * cx2[i] % MOD;
    vector<ll> x12 = convolution(cx12, true, size);
    vector<ll> result(size_x12); copy(x12.begin(), x12.begin()+size_x12, result.begin());
    return result;
  }

};

// ----------------------------------------------------------------------
// ----------------------------------------------------------------------

int main() {
  ll N; cin >> N; N *= 2;
  ll h[N]; rep(i,N) cin >> h[i]; sort(h,h+N);
  map<ll, ll> m; rep(i,N) m[h[i]]++;

  for (auto x: m) {
    if (x.second>N/2) {
      cout << 0 << endl;
      return 0;
    }
  }

  c_fac();
  deque<vector<ll>> dq;
  for (auto x: m) {
    ll l = x.second/2+1;
    vector<ll> count(l);
    rep(i,l) count[i] = i==0 ? 1 : count[i-1]*nck(x.second-(i-1)*2,2)%MOD*inv(i)%MOD;
    if (count.size()>=2) dq.push_back(count);
  }

  while (dq.size()>=2) {
    FastNumberTheoreticTransform FNTT(dq[0].size()+dq[1].size());
    vector<ll> v = FNTT.calc(dq[0],dq[1]);
    dq.pop_front(); dq.pop_front(); dq.push_back(v);
  }
  vector<ll> mul;
  if (dq.size()) mul = dq[0];
  else mul = {1};
  vector<ll> num(N); rep(i,N) num[i] = i==0 ? 1 : num[i-1]*nck(i*2,2)%MOD*inv(i)%MOD;
  // debug(all(mul)); debug(all(num));

  ll result = 0;
  rep(i,mul.size()) result = i%2==0 ? (result+num[N/2-i]*mul[i]%MOD)%MOD : (result-num[N/2-i]*mul[i]%MOD+MOD)%MOD;
  cout << result << endl;
  return 0;
}

Measured memory_bytes: 20668