// Template #include #include #include #include #include #include #include #include #include #include #include #include #include #define rep_override(x, y, z, name, ...) name #define rep2(i, n) for (int i = 0; i < (int)(n); ++i) #define rep3(i, l, r) for (int i = (int)(l); i < (int)(r); ++i) #define rep(...) rep_override(__VA_ARGS__, rep3, rep2)(__VA_ARGS__) #define all(x) (x).begin(), (x).end() using namespace std; using ll = long long; constexpr int inf = 1001001001; constexpr ll infll = 3003003003003003003LL; template inline bool chmin(T &x, const T &y) { if (x > y) { x = y; return true; } return false; } template inline bool chmax(T &x, const T &y) { if (x < y) { x = y; return true; } return false; } template istream &operator>>(istream &is, vector &vec) { for (T &element : vec) is >> element; return is; } template ostream &operator<<(ostream &os, const vector &vec) { for (int i = 0, vec_len = (int)vec.size(); i < vec_len; ++i) { os << vec[i] << (i + 1 == vec_len ? "" : " "); } return os; } struct IOSET { IOSET() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(10); } } ioset; // Mod-Int #include template struct ModInt { static_assert(mod >= 1 && mod < (1u << 31)); unsigned int val; ModInt() : val(0) {} ModInt(long long x) : val(x < 0 ? x % mod + mod : (unsigned long long)x % mod) {} ModInt &operator+=(const ModInt &x) { val += x.val; if (val >= mod) val -= mod; return *this; } ModInt &operator-=(const ModInt &x) { if (val < x.val) val += mod; val -= x.val; return *this; } ModInt &operator*=(const ModInt &x) { unsigned long long s = (unsigned long long)val * x.val; val = (unsigned int)(s % mod); return *this; } ModInt operator+() const { return *this; } ModInt operator-() const { return ModInt(0u) - *this; } friend ModInt operator+(const ModInt &x, const ModInt &y) { return ModInt(x) += y; } friend ModInt operator-(const ModInt &x, const ModInt &y) { return ModInt(x) -= y; } friend ModInt operator*(const ModInt &x, const ModInt &y) { return ModInt(x) *= y; } friend std::istream &operator>>(std::istream &is, ModInt &x) { is >> x.val; // x.value %= mod; return is; } friend std::ostream &operator<<(std::ostream &os, const ModInt &x) { os << x.val; return os; } ModInt pow(unsigned long long x) const { ModInt res(1), s(*this); while (x) { if (x & 1) res *= s; s *= s; x >>= 1; } return res; } // --- prime number --- ModInt &operator/=(const ModInt &x) { *this *= x.pow(mod - 2); return *this; } friend ModInt operator/(const ModInt &x, const ModInt &y) { return ModInt(x) /= y; } }; // Main int main() { constexpr unsigned mod = 998244353; using Mint = ModInt; int n; cin >> n; vector> g(n); rep(i, n - 1) { int u, v; cin >> u >> v; --u; --v; g[u].push_back(v); g[v].push_back(u); } vector sz(n, 1); auto dfs = [&](auto &&dfs, int v, int p) -> int { for (int u : g[v]) { if (u == p) continue; sz[v] += dfs(dfs, u, v); } return sz[v]; }; dfs(dfs, 0, -1); Mint ans(0); rep(v, n) { for (int u : g[v]) { if (sz[u] > sz[v]) continue; ans += Mint(sz[u] - 1) * Mint(sz[u]) + Mint(n - sz[u] - 1) * Mint(n - sz[u]); } } ans /= Mint(n) * Mint(n - 1); ans /= Mint(n - 1); cout << ans << '\n'; }