#include #include #define rep2(i,k,n) for(i64 i=(i64)(k);i<(i64)(n);i++) #define rep(i,n) rep2(i,0,n) #define all(x) begin(x),end(x) #ifdef ENV_LOCAL #define dump if (1) cerr #else #define dump if (0) cerr #endif using namespace std; using namespace std::string_literals; using i32 = int32_t; using i64 = int64_t; using f64 = double; using f80 = long double; using vi32 = vector; using vi64 = vector; /* * harudake::modint * * Copyright (c) 2021 prime number * * This software is released under the MIT license. * see https://opensource.org/licenses/MIT * */ namespace harudake { template class static_modint; using modint_1000000007 = static_modint; using modint_998244353 = static_modint; template static_modint add(const static_modint lhs, const static_modint rhs) { base_t tmp = lhs.val + rhs.val; if (tmp >= MOD) tmp -= MOD; return static_modint::make_raw(tmp); } template static_modint sub(const static_modint lhs, const static_modint rhs) { base_t tmp = lhs.val + MOD - rhs.val; if (tmp >= MOD) tmp -= MOD; return static_modint::make_raw(tmp); } template static_modint mul(const static_modint lhs, const static_modint rhs) { base_t tmp = lhs.val * rhs.val; tmp %= MOD; return static_modint::make_raw(tmp); } // data types must be signed integer inline int64_t inv (const int64_t a, const int64_t p) { return (a == 1 ? 1 : (1 - p * inv(p%a, a)) / a + p); }; template static_modint div(const static_modint lhs, const static_modint rhs) { base_t tmp = lhs.val * inv(rhs.val, MOD); tmp %= MOD; return static_modint::make_raw(tmp); } template static_modint pow(const static_modint base, const uint64_t index) { if (index == 0) return static_modint { 1 }; if (index % 2 == 1) { return pow(base, index - 1) * base; } else { auto half = pow(base, index / 2); return half * half; } } template class static_modint { using modint = static_modint; public: static constexpr base_t mod = MOD; static_modint() : val(0) {} static_modint(const base_t x) : val(x % MOD) {} static_modint(const modint&) = default; modint& operator=(const modint&) = default; modint& operator=(const base_t x) { val = x % MOD; return *this; } modint operator-() const { return val == 0 ? 0 : MOD - val; } explicit operator base_t() const { return val; } base_t get() const { return val; } constexpr base_t get_mod() const { return mod; } static modint make_raw(const base_t raw) { modint res; res.val = raw; return res; } private: friend modint add(const modint, const modint); friend modint sub(const modint, const modint); friend modint mul(const modint, const modint); friend modint div(const modint, const modint); base_t val; }; template static_modint operator+(const static_modint lhs, const static_modint rhs) { return add(lhs, rhs); } template static_modint operator-(const static_modint lhs, const static_modint rhs) { return sub(lhs, rhs); } template static_modint operator*(const static_modint lhs, const static_modint rhs) { return mul(lhs, rhs); } template static_modint operator/(const static_modint lhs, const static_modint rhs) { return div(lhs, rhs); } template static_modint operator^(const static_modint lhs, const uint64_t rhs) { return pow(lhs, rhs); } template static_modint& operator+=(static_modint& lhs, const static_modint rhs) { return lhs = lhs + rhs; } template static_modint& operator-=(static_modint& lhs, const static_modint rhs) { return lhs = lhs - rhs; } template static_modint& operator*=(static_modint& lhs, const static_modint rhs) { return lhs = lhs * rhs; } template static_modint& operator/=(static_modint& lhs, const static_modint rhs) { return lhs = lhs / rhs; } template static_modint& operator^=(static_modint& lhs, const uint64_t rhs) { return lhs = lhs ^ rhs; } } // namespace harudake using namespace harudake; using modint = modint_998244353; pair dfs(const vector& g, i32 n, i32 i, i32 p = -1) { i32 sz = 1; modint ans(0); for (auto&& to : g[i]) { if (to == p) continue; auto [csz, cval] = dfs(g, n, to, i); ans += cval; sz += csz; } if (sz < n) { modint mn(n); modint mk(sz); ans += (mk*(mk-modint(1)) + (mn-mk)*(mn-mk-modint(1))) / (mn * (mn - modint(1))); } return make_pair(sz, ans); } int main() { ios::sync_with_stdio(false); cin.tie(nullptr); i64 n; cin>>n; vector g(n); rep(i,n-1) { i32 u,v; cin>>u>>v; --u;--v; g[u].push_back(v); g[v].push_back(u); } auto [sz, ans] = dfs(g, n, 0); ans /= modint(n-1); cout<