#include<bits/stdc++.h>
using namespace std;
#define IOS std::ios::sync_with_stdio(false),cin.tie(0),cout.tie(0);
// #define int long long
// #define ull unsigned long long
#define fi first
#define se second
#define pi pair<int,int>

const int N=1e6+10;
// const int INF=1e18;
const int mod=998244353;

int n;
int fa[N];
int sz[N];
int rt[N];
int xx[N],yy[N];
int ls[N*16],rs[N*16],tot=0;

int quickpow(int a,int b){
    a%=mod;
    long long ans=1;
    while(b){
        if(b&1) ans=ans*a%mod;
        b>>=1;
        a=1ll*a*a%mod;
    }
    return ans;
}

int find(int xt){
    int x=xt;
    while(fa[x]!=x){
        x=fa[x];
    }
    while(fa[xt]!=xt){
        xt=fa[xt];
        fa[xt]=x;
    }
    return x;
}

void insert(int &t,int l,int r,int p){
    // cerr<<"insert "<<l<<" "<<r<<" "<<t<<"\n";
    if(!t) t=++tot;
    if(tot>=N*16){
        cout<l<<" "<<r<<"\n";
        // cout<<"WAWAWA\n";
        exit(0);
    }
    if(l==r){
        return;
    }
    int mid=l+r>>1;
    if(p<=mid) insert(ls[t],l,mid,p);
    else insert(rs[t],mid+1,r,p);
}

bool ok=0;

int mergetree(int x,int y,int ll,int rr){
    // cerr<<"merge "<<ll<<" "<<rr<<"\n";
    if(!x||!y) return x+y;    
    if(ll==rr) {
        // cerr<<"mt "<<ll<<" "<<rr<<"\n";
        ok=1;
    }
    int mid=ll+rr>>1;
    ls[y]=mergetree(ls[x],ls[y],ll,mid);
    rs[y]=mergetree(rs[x],rs[y],mid+1,rr);
    return y;
}

void merge(int x,int y){
    int fx=find(x);
    int fy=find(y);
    mergetree(rt[fx],rt[fy],1,n);
    // cout<<fx<<" "<<fy<<"\n";
    if(fx==fy) return;
    fa[fx]=fy;
    sz[fy]+=sz[fx];
    // cout<<fy<<"\n";
}

void solve(){
    cin>>n;
    for(int i=1;i<=n;i++){
        fa[i]=i;
        sz[i]=1;
        insert(rt[i],1,n,i);
    }
    bool can=1;
    for(int i=1;i<n;i++){
        cin>>xx[i]>>yy[i];
    }
    for(int i=1;i<n;i++){
        int x,y;
        cin>>x>>y;
        insert(rt[x],1,n,y);
    }
    long long ans=1;
    for(int i=1;i<n;i++){
        ans*=1ll*quickpow(sz[find(xx[i])]*sz[find(yy[i])],mod-2);
        ans%=mod;
        ok=0;
        merge(xx[i],yy[i]);
        if(!ok) can=0;
    }
    if(!can){
        cout<<0<<"\n";
        return;
    }
    cout<<ans<<"\n";
}

signed main(){
    IOS
    int _=1;
    // cin>>_;
    while(_--){
        solve();
    }
}

answer.code: In function ‘void insert(int&, int, int, int)’:
answer.code:48:15: error: invalid operands of types ‘int’ and ‘const char [2]’ to binary ‘operator<<’
   48 |         cout<l<<" "<<r<<"\n";
      |              ~^~~~~
      |              |  |
      |              |  const char [2]
      |              int