#include<iostream>
#include<cstdio>
#define int long long
using namespace std;
const int MX=1000010;
const int p=998244353;

int N;
int ar[MX], br[MX], cr[MX], dr[MX];
int fa[MX], siz[MX], low[MX];
int head[MX], cnt=0, f[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;
}
struct edge{int nxt, to;}e[2*MX];
inline void ae(int u, int v){e[++cnt].to=v; e[cnt].nxt=head[u]; head[u]=cnt;}
int qpow(int x, int pow)
{
    int ans=1;
    while(pow)
    {
        if(pow&1) ans=ans*x%p;
        x=x*x%p;
        pow>>=1;
    }
    return ans;
}
int inv(int x) {return qpow(x,p-2);}
int find(int x){return x==fa[x]?fa[x]:fa[x]=find(fa[x]);}
void dfs(int x, int father)
{
    f[x]=father; //cout << "fa[" << x << "]=" << father << '\n';
    for(int i=head[x];i;i=e[i].nxt)
    {
        int y=e[i].to;
        if(y==father) continue;
        dfs(y,x);
    }
}
signed main()
{
    // freopen("testdata.in","r",stdin);
    N=read();
    for(int i=1;i<=N;i++) fa[i]=low[i]=i, siz[i]=1;
    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();
        ae(cr[i],dr[i]);
        ae(dr[i],cr[i]);
    }
    dfs(1,0);
    int ans=1;
    for(int i=1;i<N;i++)
    {
        int v=find(ar[i]), u=find(br[i]);
        // cout << v << ", u=" << u << '\n';
        if(v==find(f[low[u]])) {}
        else if(u==find(f[low[v]])) low[v]=low[u];
        else {cout << "0\n"; return 0;}
        ans=ans*siz[u]%p*siz[v]%p;
        siz[v]+=siz[u];
        fa[u]=v;
    }
    cout << inv(ans) << '\n';
    return (0-0);
}