#include #define REP_(i, a_, b_, a, b, ...) \ for (int i = (a), END_##i = (b); i < END_##i; ++i) #define REP(i, ...) REP_(i, __VA_ARGS__, __VA_ARGS__, 0, __VA_ARGS__) #define ALL(x) std::begin(x), std::end(x) using i64 = long long; #include using Mint = atcoder::modint998244353; std::ostream &operator<<(std::ostream &os, const Mint &m) { return os << m.val(); } template inline bool chmax(T &a, U b) { return a < b and ((a = std::move(b)), true); } template inline bool chmin(T &a, U b) { return a > b and ((a = std::move(b)), true); } template inline int ssize(const T &a) { return (int)std::size(a); } template std::istream &operator>>(std::istream &is, std::vector &a) { for (auto &x : a) is >> x; return is; } template std::ostream &operator<<(std::ostream &os, const std::pair &a) { return os << "(" << a.first << ", " << a.second << ")"; } template std::ostream &print_seq(const Container &a, std::string_view sep = " ", std::string_view ends = "\n", std::ostream &os = std::cout) { auto b = std::begin(a), e = std::end(a); for (auto it = std::begin(a); it != e; ++it) { if (it != b) os << sep; os << *it; } return os << ends; } template struct is_iterable : std::false_type {}; template struct is_iterable())), decltype(std::end(std::declval()))>> : std::true_type {}; template ::value && !std::is_same::value && !std::is_same::value>> std::ostream &operator<<(std::ostream &os, const T &a) { return print_seq(a, ", ", "", (os << "{")) << "}"; } #ifdef ENABLE_DEBUG #include "debug_dump.hpp" #else #define DUMP(...) #endif using namespace std; auto solve() { 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); } const Mint total = Mint(n) * Mint(n - 1).pow(2) / 2; Mint connected_count = 0; auto dfs = [&](auto &dfs, int v, int p) -> int { int sz = 1; for (auto u : g[v]) { if (u == p) continue; int a_size = dfs(dfs, u, v); int b_size = n - a_size; connected_count += Mint(a_size) * Mint(a_size - 1) / 2; connected_count += Mint(b_size) * Mint(b_size - 1) / 2; sz += a_size; } return sz; }; dfs(dfs, 0, -1); DUMP(connected_count, total); return connected_count / total; } int main() { ios_base::sync_with_stdio(false), cin.tie(nullptr); cout << solve() << "\n"; }