#include<bits/stdc++.h>
using namespace std;
typedef pair<int,int> PII;
typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
const int MX=1000010;
const int p=998244353;

int N;
int ar[MX], br[MX], cr[MX], dr[MX];
int fa[MX], siz[MX];
map<int,int> blo[MX];
vector<int> v[MX];
int read()
{
    int r=0, f=1; char ch=getchar();
    while(ch<'0'||ch>'9') {if(ch=='-') f=-1; ch=getchar();}
    while(ch>='0'&&ch<='9') {r=r*10+ch-'0'; ch=getchar();}
    return r*f;
}
ll qmul(ll a, ll b)
{
    ll tmp=a*b-(int)((ld)a/p*b+0.5)*p; tmp%=p;
    return tmp<ll(0)?tmp+p:tmp;
}
ll qpow(ll x, ll pow)
{
    ll ans=1;
    while(pow)
    {
        if(pow&1) ans=ans*x%p;
        x=x*x%p;
        pow>>=1;
    }
    return ans;
}
ll inv(ll x){ return qpow(x,p-2);}
int find(int x){return x==fa[x]?fa[x]:fa[x]=find(fa[x]);}
void merge(int x, int y) 
{
    x=find(x); y=find(y);
    if(siz[x]<siz[y]) swap(x,y);
    fa[y]=x; siz[x]+=siz[y];
    for(auto u:v[y]) 
        v[x].emplace_back(u);
    for(auto [id,num]:blo[y])
    {
        // cout << "   id=" << id << ", num=" << num << '\n';
        blo[x][id]+=num;
    }
        
}
int main()
{
    // freopen("testdata.in","r",stdin);
    N=read();
    for(int i=1;i<=N;i++) fa[i]=i, siz[i]=1, v[i].emplace_back(i);
    for(int i=1;i<N;i++)
    {   
        ar[i]=read(), br[i]=read();
    }
    for(int i=1;i<N;i++)
    {
        cr[i]=read(), dr[i]=read();
        blo[cr[i]][dr[i]]++;
        blo[dr[i]][cr[i]]++;
    }
    ll ans=1;
    for(int i=1;i<N;i++)
    {
        ar[i]=find(ar[i]);
        br[i]=find(br[i]);
        ll bas=inv(siz[ar[i]]*siz[br[i]]);
        if(siz[ar[i]]>siz[br[i]]) swap(ar[i],br[i]);
        ll num=0;
        for(auto u:v[ar[i]])
        {
            num+=blo[br[i]][u];
            // cout << "   u=" << u << ", num=" << num << '\n';
        }
        // cout << "bas=" << siz[ar[i]]*siz[br[i]] << ", fac=" << num << '\n';        
        merge(ar[i],br[i]);
        ans=qmul(qmul(ans,bas),num);
    }
    cout << ans << '\n';
    return (0-0);
}