#include<cstdio>
#include<vector>
#include<queue>
#include<cstring>
#include<iostream>
#include<algorithm>
#include<ctime>
#include<random>
#include<assert.h>
#define pb emplace_back
#define mp make_pair
#define fi first
#define se second
#define dbg(x) cerr<<"In Line "<< __LINE__<<" the "<<#x<<" = "<<x<<'\n'
#define dpi(x,y) cerr<<"In Line "<<__LINE__<<" the "<<#x<<" = "<<x<<" ; "<<"the "<<#y<<" = "<<y<<'\n'
#define DE(fmt,...) fprintf(stderr, "Line %d : " fmt "\n",__LINE__,##__VA_ARGS__)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int>pii;
typedef pair<ll,int>pli;
typedef pair<ll,ll>pll;
typedef pair<int,ll>pil;
typedef vector<int>vi;
typedef vector<ll>vll;
typedef vector<pii>vpii;
typedef vector<pll>vpll;
template<typename T>T cmax(T &x, T y){return x=x>y?x:y;}
template<typename T>T cmin(T &x, T y){return x=x<y?x:y;}
template<typename T>
T &read(T &r){
	r=0;bool w=0;char ch=getchar();
	while(ch<'0'||ch>'9')w=ch=='-'?1:0,ch=getchar();
	while(ch>='0'&&ch<='9')r=r*10+(ch^48),ch=getchar();
	return r=w?-r:r;
}
template<typename T1,typename... T2>
void read(T1 &x,T2& ...y){read(x);read(y...);}
const int mod=998244353;
inline void cadd(int &x,int y){x=(x+y>=mod)?(x+y-mod):(x+y);}
inline void cdel(int &x,int y){x=(x-y<0)?(x-y+mod):(x-y);}
inline int add(int x,int y){return (x+y>=mod)?(x+y-mod):(x+y);}
inline int del(int x,int y){return (x-y<0)?(x-y+mod):(x-y);}
int qpow(int x,int y){
	int s=1;
	while(y){
		if(y&1)s=1ll*s*x%mod;
		x=1ll*x*x%mod;
		y>>=1;
	}
	return s;
}
const int N=4010;
int n;
vi eg[N];
int f[N][N][2],g[N][2],siz[N];
void dfs(int x,int fa){
	f[x][0][0]=1;siz[x]=1;
	for(auto v:eg[x])if(v!=fa){
		dfs(v,x);
		for(int i=0;i<=siz[x]/2;i++)
			if(f[x][i][0]||f[x][i][1])
				for(int j=0;j<=siz[v]/2;j++){
					//link(x,v)
					cadd(g[i+j+1][1],1ll*f[x][i][0]*f[v][j][0]%mod);
					//not link
					cadd(g[i+j][0],1ll*f[x][i][0]*f[v][j][0]%mod);
					cadd(g[i+j][0],1ll*f[x][i][0]*f[v][j][1]%mod);
					cadd(g[i+j][1],1ll*f[x][i][1]*f[v][j][0]%mod);
					cadd(g[i+j][1],1ll*f[x][i][1]*f[v][j][1]%mod);
				}
		siz[x]+=siz[v];
		for(int i=0;i<=siz[x]/2;i++){
			f[x][i][0]=g[i][0];
			f[x][i][1]=g[i][1];
			g[i][0]=g[i][1]=0;
		}
	}
}
int h[N],t[N],ct[N];
signed main(){
	#ifdef do_while_true
//		assert(freopen("data.in","r",stdin));
//		assert(freopen("data.out","w",stdout));
	#endif
	read(n);
	h[0]=1;ct[0]=1;
	for(int i=1;i<=2*n;i++){
		for(int j=0;j<i;j++)cadd(t[j+1],h[j]);
		for(int j=1;j<i;j++)cadd(t[j-1],1ll*h[j]*j%mod);
		for(int j=0;j<=i;j++)h[j]=t[j],t[j]=0;
		if(i%2==0)ct[i/2]=h[0];
	}
	for(int i=1;i<2*n;i++){
		int u,v;read(u,v);
		eg[u].pb(v);eg[v].pb(u);
	}
	dfs(1,0);
	int ans=0;
	for(int i=0;i<=n;i++){
		int s=1ll*add(f[1][i][0],f[1][i][1])*ct[n-i]%mod;
		if(i&1)cdel(ans,s);
		else cadd(ans,s);
	}
	cout<<ans<<'\n';
    #ifdef do_while_true
//		cerr<<'\n'<<"Time:"<<1.0*clock()/CLOCKS_PER_SEC*1000<<" ms"<<'\n';
	#endif
	return 0;
}