#pragma GCC optimize(2)
#pragma GCC optimize(3)
#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
#define debug(x) cout << #x << "=" << x << endl
//using i128 = __int128_t;
//#define int long long
typedef pair<int,int> PII;
typedef long long ll;
inline void read(int &x){
    char ch=getchar();int f=1;x=0;
    while(!isdigit(ch) && ch^'-') ch=getchar();
    if(ch=='-') f=-1,ch=getchar();
    while(isdigit(ch)) x=x*10+ch-'0',ch=getchar();
    x*=f;
}
void write(int x){
    if(x<0)
    putchar('-'),x=-x;
    if(x>9)
    write(x/10);
    putchar(x%10+'0');
    return;
}

using i64 = long long;
template<class T>
constexpr T power(T a, i64 b) {
    T res {1};
    for (; b; b /= 2, a *= a) {
        if (b % 2) {
            res *= a;
        }
    }
    return res;
}

constexpr i64 mul(i64 a, i64 b, i64 p) {
    i64 res = a * b - i64(1.L * a * b / p) * p;
    res %= p;
    if (res < 0) {
        res += p;
    }
    return res;
}

template<i64 P>
struct MInt {
    i64 x;
    constexpr MInt() : x {0} {}
    constexpr MInt(i64 x) : x {norm(x % getMod())} {}
    
    static i64 Mod;
    constexpr static i64 getMod() {
        if (P > 0) {
            return P;
        } else {
            return Mod;
        }
    }
    constexpr static void setMod(i64 Mod_) {
        Mod = Mod_;
    }
    constexpr i64 norm(i64 x) const {
        if (x < 0) {
            x += getMod();
        }
        if (x >= getMod()) {
            x -= getMod();
        }
        return x;
    }
    constexpr i64 val() const {
        return x;
    }
    constexpr MInt operator-() const {
        MInt res;
        res.x = norm(getMod() - x);
        return res;
    }
    constexpr MInt inv() const {
        return power(*this, getMod() - 2);
    }
    constexpr MInt &operator*=(MInt rhs) & {
        if (getMod() < (1ULL << 31)) {
            x = x * rhs.x % int(getMod());
        } else {
            x = mul(x, rhs.x, getMod());
        }
        return *this;
    }
    constexpr MInt &operator+=(MInt rhs) & {
        x = norm(x + rhs.x);
        return *this;
    }
    constexpr MInt &operator-=(MInt rhs) & {
        x = norm(x - rhs.x);
        return *this;
    }
    constexpr MInt &operator/=(MInt rhs) & {
        return *this *= rhs.inv();
    }
    friend constexpr MInt operator*(MInt lhs, MInt rhs) {
        MInt res = lhs;
        res *= rhs;
        return res;
    }
    friend constexpr MInt operator+(MInt lhs, MInt rhs) {
        MInt res = lhs;
        res += rhs;
        return res;
    }
    friend constexpr MInt operator-(MInt lhs, MInt rhs) {
        MInt res = lhs;
        res -= rhs;
        return res;
    }
    friend constexpr MInt operator/(MInt lhs, MInt rhs) {
        MInt res = lhs;
        res /= rhs;
        return res;
    }
    friend constexpr std::istream &operator>>(std::istream &is, MInt &a) {
        i64 v;
        is >> v;
        a = MInt(v);
        return is;
    }
    friend constexpr std::ostream &operator<<(std::ostream &os, const MInt &a) {
        return os << a.val();
    }
    friend constexpr bool operator==(MInt lhs, MInt rhs) {
        return lhs.val() == rhs.val();
    }
    friend constexpr bool operator!=(MInt lhs, MInt rhs) {
        return lhs.val() != rhs.val();
    }
    friend constexpr bool operator<(MInt lhs, MInt rhs) {
        return lhs.val() < rhs.val();
    }
};

template<>
i64 MInt<0>::Mod = 998244353;

constexpr int P = 998244353;
using Z = MInt<P>;

struct Comb {
    int n;
    std::vector<Z> _fac;
    std::vector<Z> _invfac;
    std::vector<Z> _inv;
    
    Comb() : n{0}, _fac{1}, _invfac{1}, _inv{0} {}
    Comb(int n) : Comb() {
        init(n);
    }
    
    void init(int m) {
        m = std::min<i64>(m, Z::getMod() - 1);
        if (m <= n) return;
        _fac.resize(m + 1);
        _invfac.resize(m + 1);
        _inv.resize(m + 1);
        
        for (int i = n + 1; i <= m; i++) {
            _fac[i] = _fac[i - 1] * i;
        }
        _invfac[m] = _fac[m].inv();
        for (int i = m; i > n; i--) {
            _invfac[i - 1] = _invfac[i] * i;
            _inv[i] = _invfac[i] * _fac[i - 1];
        }
        n = m;
    }
    
    Z fac(int m) {
        if (m > n) init(2 * m);
        return _fac[m];
    }
    Z invfac(int m) {
        if (m > n) init(2 * m);
        return _invfac[m];
    }
    Z inv(int m) {
        if (m > n) init(2 * m);
        return _inv[m];
    }
    Z binom(int n, int m) {
        if (n < m || m < 0) return 0;
        return fac(n) * invfac(m) * invfac(n - m);
    }
} comb;
int n;
void rCL(){
	cin>>n;
	vector<vector<int>>e(2*n+1);
	for(int i=1;i<=2*n-1;i++){
		int u,v;
		cin>>u>>v;
		e[u].push_back(v);
		e[v].push_back(u);
	}    

	vector<vector<vector<Z>>>f(2*n+1,vector<vector<Z>>(2*n+1,vector<Z>(2,0)));
	vector<int>sz(2*n+1);

	auto dfs=[&](auto dfs,int u,int fa)->void{
       // cout<<u<<endl;
		sz[u]=1;f[u][0][0]=1;
		for(auto v:e[u]){
			vector<vector<Z>>g(2*n+1,vector<Z>(2,0));
            //g[0][0]=1;
			if(v==fa)continue;
			dfs(dfs,v,u);

			for(int i=0;i<=sz[u]/2;i++){
				for(int j=0;j<=sz[v]/2;j++){
					g[i+j][0]+=f[u][i][0]*(f[v][j][0]+f[v][j][1]);
					g[i+j][1]+=f[u][i][1]*(f[v][j][0]+f[v][j][1]);
					g[i+1+j][1]+=f[u][i][0]*f[v][j][0];
				}
			}
            //cout<<"U"<<u<<endl;
			for(int i=0;i<=sz[u]/2+sz[v]/2+1;i++){
               // cout<<u<<' '<<i<<' '<<f[u][i][0]<<endl;
                //cout<<u<<' '<<i<<' '<<f[u][i][1]<<endl;
				f[u][i][0]=g[i][0];
				f[u][i][1]=g[i][1];
			}

			sz[u]+=sz[v];
		}
	};
    Z res=0;
    vector<Z>f2(n+1);
    dfs(dfs,1,0);
    //cout<<1<<endl;
    f2[0]=1;
    for(int i=1;i<=n;i++){
        if(i==1)f2[i]=(Z)1/2;
        else{
            f2[i]=f2[i-1]/2;
        }
    }
    for(int i=0;i<=n;i++){
        Z x=f[1][i][0]+f[1][i][1];
       // cout<<f[1][i][0]<<' '<<f[1][i][1]<<endl;
       // Z y=1;
        Z y=comb.binom(2*n-2*i,n-i)*comb.fac(n-i)*f2[n-i];
        //cout<<comb.binom(2*n-2*i,n-i)<<' '<<comb.fac(n-i)<<' '<<f2[n-i]<<endl;
        //cout<<"y"<<y<<endl;
        if(i&1){
            res-=x*y;
        }else{
            res+=x*y;
        }
    }
    cout<<res<<endl;




}
signed main(){
    ios::sync_with_stdio(false);
    cin.tie(0);cout.tie(0);
    int O_o=1;
    while(O_o--){
        rCL();
    }
}