# include <bits/stdc++.h>
using namespace std;
# define IOS ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
# define int long long
# define lowbit(x) (x & (-x))
# define fi first
# define se second
// # define endl '\n'

inline int Read();

typedef pair<int, int> PII;
const int INF = 0x3f3f3f3f;
const int MOD = 998244353;
const int N = 1e6 + 10;

map <int, int> mp;

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

vector <int> v[N];
vector <PII> u;

int vis[N], f[N], siz[N], p[N], dep[N], fa[N];
int find(int x){
    if(x == f[x]) return x;
    return f[x] = find(f[x]);
}
void dfs(int x, int y, int ff){
    vis[x] = 1;
    dep[x] = y;
    fa[x] = ff;
    for(auto i : v[x]){
        if(vis[i]) continue;
        dfs(i, y + 1, x);
    }
}
void add(int x, int y){
    int xx = find(x);
    int yy = find(y);
    if(xx == yy) return;
    if(dep[yy] <= dep[xx]){
        f[xx] = yy;
        siz[yy] += siz[xx];
    }else{
        f[yy] = xx;
        siz[xx] += siz[yy];
    }
}
void Solve(){
    int n;
    cin >> n;
    for(int i = 1; i <= n; i ++){
        f[i] = i;
        siz[i] = 1;
        p[i] = 1;
    }
    u.push_back({0, 0});
    for(int i = 1; i < n; i ++){
        int x, y;
        cin >> x >> y;
        u.push_back({x, y});
    }
    for(int i = 1; i < n; i ++){
        int x, y;
        cin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1, 1, 0);
    int ans = 1;
    for(int i = 1; i < n; i ++){
        int x = u[i].fi;
        int y = u[i].se;
        int xx = find(x);
        int yy = find(y);
        if(fa[xx] == yy || fa[yy] == xx){
            int num = siz[xx] * siz[yy] % MOD;
            int pp = qmi(num, MOD - 2);
            if(fa[xx] == yy) {
                p[yy] = p[yy] * p[xx] % MOD * pp % MOD;
                ans = ans * p[yy] % MOD;
            }else{
                p[xx] = p[xx] * pp % MOD * p[yy] % MOD;
                ans = ans * p[xx] % MOD;
            }
            add(x, y);
        }else{
            ans = 0;
            break;
        }
    }
    cout << ans <<"\n";

}
signed main(){
    // IOS;
    int T = 1;
    // cin >> T;
    while (T--) 
        Solve();
    return 0;
}
inline int Read(){
    int x = 0, f = 1; char c = getchar();
    while (c < '0' || c > '9'){ if (c == '-') f = -1; c = getchar();}
    while (c >= '0' && c <= '9') x = x * 10 + c - '0', c = getchar();
    return x * f;
}