#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using uint = unsigned int;
#define rep(i,n) for(int i=0;i<int(n);i++)
#define rep1(i,n) for(int i=1;i<=int(n);i++)
#define per(i,n) for(int i=int(n)-1;i>=0;i--)
#define per1(i,n) for(int i=int(n);i>0;i--)
#define all(c) c.begin(),c.end()
#define si(x) int(x.size())
#define pb emplace_back
#define fs first
#define sc second
template<class T> using V = vector<T>;
template<class T> using VV = vector<vector<T>>;
template<class T,class U> void chmax(T& x, U y){if(x<y) x=y;}
template<class T,class U> void chmin(T& x, U y){if(y<x) x=y;}
template<class T> void mkuni(V<T>& v){sort(all(v));v.erase(unique(all(v)),v.end());}
template<class S,class T> ostream& operator<<(ostream& o,const pair<S,T> &p){
	return o<<"("<<p.fs<<","<<p.sc<<")";
}
template<class T> ostream& operator<<(ostream& o,const vector<T> &vc){
	o<<"{";
	for(const T& v:vc) o<<v<<",";
	o<<"}";
	return o;
}
constexpr ll TEN(int n) { return (n == 0) ? 1 : 10 * TEN(n-1); }

#ifdef LOCAL
#define show(x) cerr << "LINE" << __LINE__ << " : " << #x << " = " << (x) << endl
void dmpr(ostream& os){os<<endl;}
template<class T,class... Args>
void dmpr(ostream&os,const T&t,const Args&... args){
	os<<t<<" ~ ";
	dmpr(os,args...);
}
#define shows(...) cerr << "LINE" << __LINE__ << " : ";dmpr(cerr,##__VA_ARGS__)
#define dump(x) cerr << "LINE" << __LINE__ << " : " << #x << " = {";  \
	for(auto v: x) cerr << v << ","; cerr << "}" << endl;
#else
#define show(x) void(0)
#define dump(x) void(0)
#define shows(...) void(0)
#endif
template<unsigned int mod_>
struct ModInt{
	using uint = unsigned int;
	using ll = long long;
	using ull = unsigned long long;

	constexpr static uint mod = mod_;

	uint v;
	ModInt():v(0){}
	ModInt(ll _v):v(normS(_v%mod+mod)){}
	explicit operator bool() const {return v!=0;}
	static uint normS(const uint &x){return (x<mod)?x:x-mod;}		// [0 , 2*mod-1] -> [0 , mod-1]
	static ModInt make(const uint &x){ModInt m; m.v=x; return m;}
	ModInt operator+(const ModInt& b) const { return make(normS(v+b.v));}
	ModInt operator-(const ModInt& b) const { return make(normS(v+mod-b.v));}
	ModInt operator-() const { return make(normS(mod-v)); }
	ModInt operator*(const ModInt& b) const { return make((ull)v*b.v%mod);}
	ModInt operator/(const ModInt& b) const { return *this*b.inv();}
	ModInt& operator+=(const ModInt& b){ return *this=*this+b;}
	ModInt& operator-=(const ModInt& b){ return *this=*this-b;}
	ModInt& operator*=(const ModInt& b){ return *this=*this*b;}
	ModInt& operator/=(const ModInt& b){ return *this=*this/b;}
	ModInt& operator++(int){ return *this=*this+1;}
	ModInt& operator--(int){ return *this=*this-1;}
	ll extgcd(ll a,ll b,ll &x,ll &y) const{
		ll p[]={a,1,0},q[]={b,0,1};
		while(*q){
			ll t=*p/ *q;
			rep(i,3) swap(p[i]-=t*q[i],q[i]);
		}
		if(p[0]<0) rep(i,3) p[i]=-p[i];
		x=p[1],y=p[2];
		return p[0];
	}
	ModInt inv() const {
		ll x,y;
		extgcd(v,mod,x,y);
		return make(normS(x+mod));
	}
	ModInt pow(ll p) const {
		if(p<0) return inv().pow(-p);
		ModInt a = 1;
		ModInt x = *this;
		while(p){
			if(p&1) a *= x;
			x *= x;
			p >>= 1;
		}
		return a;
	}
	bool operator==(const ModInt& b) const { return v==b.v;}
	bool operator!=(const ModInt& b) const { return v!=b.v;}
	friend istream& operator>>(istream &o,ModInt& x){
		ll tmp;
		o>>tmp;
		x=ModInt(tmp);
		return o;
	}
	friend ostream& operator<<(ostream &o,const ModInt& x){ return o<<x.v;}
};
using mint = ModInt<998244353>;
V<mint> fact,ifact;
mint Choose(int a,int b){
	if(b<0 || a<b) return 0;
	return fact[a] * ifact[b] * ifact[a-b];
}
void InitFact(int N){
	fact.resize(N);
	ifact.resize(N);
	fact[0] = 1;
	rep1(i,N-1) fact[i] = fact[i-1] * i;
	ifact[N-1] = fact[N-1].inv();
	for(int i=N-2;i>=0;i--) ifact[i] = ifact[i+1] * (i+1);
}
int bsr(int x) { return 31 - __builtin_clz(x); }
void ntt(bool type, V<mint>& c) {
	const mint G = 3;	//primitive root

	int N = int(c.size());
	int s = bsr(N);
	assert(1 << s == N);

	V<mint> a = c, b(N);
	rep1(i,s){
		int W = 1 << (s - i);
		mint base = G.pow((mint::mod - 1)>>i);
		if(type) base = base.inv();
		mint now = 1;
		for(int y = 0; y < N / 2; y += W) {
			for (int x = 0; x < W; x++) {
				auto l = a[y << 1 | x];
				auto r = now * a[y << 1 | x | W];
				b[y | x] = l + r;
				b[y | x | N >> 1] = l - r;
			}
			now *= base;
		}
		swap(a, b);
	}
	c = a;
}

V<mint> multiply_ntt(const V<mint>& a, const V<mint>& b) {
	int A = int(a.size()), B = int(b.size());
	if (!A || !B) return {};
	int lg = 0;
	while ((1 << lg) < A + B - 1) lg++;
	int N = 1 << lg;
	V<mint> ac(N), bc(N);
	for (int i = 0; i < A; i++) ac[i] = a[i];
	for (int i = 0; i < B; i++) bc[i] = b[i];
	ntt(false, ac);
	ntt(false, bc);
	for (int i = 0; i < N; i++) {
		ac[i] *= bc[i];
	}
	ntt(true, ac);
	V<mint> c(A + B - 1);
	mint iN = mint(N).inv();
	for (int i = 0; i < A + B - 1; i++) {
		c[i] = ac[i] * iN;
	}
	return c;
}
int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);		//DON'T USE scanf/printf/puts !!
	cout << fixed << setprecision(20);
	InitFact(100010);

	int N; cin >> N; N *= 2;
	V<int> as;
	{
		map<int,int> mp;
		rep(i,N){
			int x; cin >> x; mp[x]++;
		}
		for(auto it: mp) as.pb(it.sc);
	}

	priority_queue<V<mint>,VV<mint>,function<bool(V<mint>&,V<mint>&)>> q([](V<mint>& l,V<mint>& r){return si(l) > si(r);});

	for(int a: as){
		V<mint> f(a/2+1);
		rep(k,a/2+1){
			f[k] = fact[a] * ifact[a-2*k] * ifact[k] * mint(2).pow(-k);
		}
		q.push(f);
	}
	while(si(q) > 1){
		auto a = q.top(); q.pop();
		auto b = q.top(); q.pop();
		q.push(multiply_ntt(a,b));
	}
	auto f = q.top();
	mint ans = 0;
	rep(k,si(f)) ans += (fact[N-2*k] * ifact[N/2-k] / mint(2).pow(N/2-k)) * f[k] * (k%2==0 ? 1 : -1);
	cout << ans << endl;
}


Measured memory_bytes: 11536