#include #include #include #include #include #include #include #define rep(i, a, b) for (int i = int(a); i < int(b); i++) using namespace std; using ll = long long int; using P = pair; // clang-format off #ifdef _DEBUG_ #define dump(...) do{ cerr << __LINE__ << ":\t" << #__VA_ARGS__ << " = "; debug_print(__VA_ARGS__); } while(false) template void debug_print(const T &t, const Ts &...ts) { cerr << t; ((cerr << ", " << ts), ...); cerr << endl; } #else #define dump(...) do{ } while(false) #endif template vector make_v(size_t a, T b) { return vector(a, b); } template auto make_v(size_t a, Ts... ts) { return vector(a, make_v(ts...)); } template bool chmin(T &a, const T& b) { if (a > b) {a = b; return true; } return false; } template bool chmax(T &a, const T& b) { if (a < b) {a = b; return true; } return false; } template void print(const T& t, const Ts&... ts) { cout << t; ((cout << ' ' << ts), ...); cout << '\n'; } template void input(Ts&... ts) { (cin >> ... >> ts); } template istream &operator,(istream &in, T &t) { return in >> t; } // clang-format on template class ModInt { ll n; ModInt constexpr inverse() const { return ModInt::pow(*this, MOD - 2); } public: ModInt() : n(0) {} ModInt(ll _n) : n(((_n % MOD) + MOD) % MOD) {} ModInt operator+=(const ModInt &m) { n += m.n; if (n >= MOD) n -= MOD; return *this; } ModInt operator-=(const ModInt &m) { n -= m.n; if (n < 0) n += MOD; return *this; } ModInt operator*=(const ModInt &m) { n *= m.n; if (n >= MOD) n %= MOD; return *this; } ModInt operator/=(const ModInt &m) { (*this) *= m.inverse(); return *this; } friend ModInt operator+(ModInt t, const ModInt &m) { return t += m; } friend ModInt operator-(ModInt t, const ModInt &m) { return t -= m; } friend ModInt operator*(ModInt t, const ModInt &m) { return t *= m; } friend ModInt operator/(ModInt t, const ModInt &m) { return t /= m; } ModInt operator=(const ll l) { n = l % MOD; if (n < 0) n += MOD; return *this; } friend ostream &operator<<(ostream &out, const ModInt &m) { out << m.n; return out; } friend istream &operator>>(istream &in, ModInt &m) { ll l; in >> l; m = l; return in; } static constexpr ModInt pow(const ModInt x, ll p) { ModInt ans = 1; for (ModInt m = x; p > 0; p /= 2, m *= m) { if (p % 2) ans *= m; } return ans; } static constexpr ll mod() { return MOD; } }; using mint = ModInt<998244353>; mint operator"" _m(unsigned long long m) { return mint(m); } int main() { cin.tie(nullptr); ios::sync_with_stdio(false); int n; cin, n; vector> g(n); rep(i, 0, n - 1) { int a, b; cin, a, b; a--; b--; g[a].emplace_back(b); g[b].emplace_back(a); } auto nC2 = [&](ll a) { return 1_m * a * (a - 1) / 2; }; mint ans = 0; auto dfs = [&](auto &f, int v, int p) -> ll { ll sz = 1; for (auto nv : g[v]) { if (nv == p) continue; ll res = f(f, nv, v); ans += nC2(res); ans += nC2(n - res); sz += res; } return sz; }; dfs(dfs, 0, -1); print(ans / nC2(n) / (n - 1)); return 0; }