#include<bits/stdc++.h>
#define int long long
#define mod 998244353ll
#define pii pair<int,int>
#define fi first
#define se second
#define mems(x,y) memset(x,y,sizeof(x))
#define pb push_back
#define db double
using namespace std;
const int maxn=1000010;
const int inf=1e18;
inline int read(){
	int x=0,f=1;
	char ch=getchar();
	while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
	while(ch>='0'&&ch<='9'){x=(x<<3)+(x<<1)+(ch-48);ch=getchar();}
	return x*f;
}
bool Mbe;

int n,ans=1;
pii a[maxn],b[maxn];
int f[maxn],siz[maxn];
int fd(int x){
	if(f[x]==x)return x;
	return f[x]=fd(f[x]);
}
inline int ksm(int a,int b=mod-2){
	int ans=1;
	while(b){
		if(b&1)ans=ans*a%mod;
		a=a*a%mod;
		b>>=1;
	}
	return ans;
}
vector<int> id[maxn];
bool vis[maxn];
void work(){
	n=read();
	for(int i=1;i<n;i++)a[i]={read(),read()};
	for(int i=1;i<n;i++)b[i]={read(),read()};
	for(int i=1;i<n;i++)id[b[i].fi].pb(i),id[b[i].se].pb(i);
	for(int i=1;i<=n;i++)f[i]=i,siz[i]=1;
	for(int i=1;i<n;i++){
		int u=fd(a[i].fi),v=fd(a[i].se);
		if(u==v){puts("0");}
		if(id[u]>id[v])swap(id[u],id[v]);
		bool fl=0;
		for(int &j:id[u])if(!vis[j]){
			if(fd(b[j].fi)==v||fd(b[j].se)==v){
				vis[j]=1;
				fl=1;break;
			}
		}
		if(!fl){puts("0");break;}
		ans=ans*siz[u]%mod*siz[v]%mod;
		f[u]=v,siz[v]+=siz[u];
		for(int j:id[v])id[u].pb(j);
	}
	ans=ksm(ans);
	printf("%lld\n",ans);
}

// \
444

bool Med;
int T;
signed main(){
//	freopen(".in","r",stdin);
//	freopen(".out","w",stdout);
	
//	ios::sync_with_stdio(0);
//	cin.tie(0);cout.tie(0);
	
//	cerr<<(&Mbe-&Med)/1048576.0<<" MB\n";
	
	T=1;
	while(T--)work();
}