#include <unordered_map>
#include <algorithm>
#include <iostream>
#include <cstring>
#include <vector>
#include <cmath>
#include <queue>
#include <set>
#include <map>

#define x first
#define y second

#define int long long

using namespace std;

typedef long long LL;
typedef unsigned long long ULL;
typedef pair<int, int> PII;

const LL mod = 998244353;
const ULL P = 13331;
const int N = 1000010;

int p[N], dep[N], fa[N], sz[N];
PII Q[N];
vector<int> G[N];

int find(int x)
{
    return p[x] == x ? x : p[x] = find(p[x]);
}

int qmi(int a, int b)
{
    int res = 1;
    while (b)
    {
        if (b & 1) res = res * a % mod;
        a = a * a % mod;
        b >>= 1;
    }
    return res;
}

void dfs(int u, int father, int depth)
{
    dep[u] = depth, fa[u] = father;
    for (auto j : G[u])
    {
        if (j == father) continue;
        dfs(j, u, depth + 1);
    }
}

void solve()
{
    int n;
    cin >> n;
    for (int i = 1; i <= n; i ++) 
    {
        p[i] = i;
        G[i].clear();
        sz[i] = 1;
    }
    
    for (int i = 0; i < n - 1; i ++)
        cin >> Q[i].x >> Q[i].y;
    
    for (int i = 0; i < n - 1; i ++)
    {
        int a, b;
        cin >> a >> b;
        G[a].push_back(b), G[b].push_back(a);
    }
    dfs(1, 0, 1);
    
    int res = 1;
    for (int i = 0; i < n - 1; i ++)
    {
        int l = Q[i].x, r = Q[i].y;
        int pl = find(p[l]), pr = find(p[r]);
        if (dep[pl] < dep[pr]) swap(pl, pr); // 保证pr在上方
        
        
        int con = find(fa[pl]);
        if (con != pr)
        {
            cout << 0 << endl;
            return ;
        }
        //printf ("sz[%lld] = %lld sz[%lld] = %lld\n", pl, sz[pl], pr, sz[pr]);
        res = (res * qmi(sz[pl] * sz[pr], mod - 2)) % mod;
        
        p[pl] = pr;
        sz[pr] += sz[pl];
    }
    cout << res << endl;
}

signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr), cout.tie(nullptr);
    int T = 1;
    // cin >> T;
    while (T --) solve();
    return 0;
}