#include #ifdef LOCAL #include #else #define debug(...) void(0) #endif #include "atcoder/modint" using namespace std; typedef long long ll; #define all(x) begin(x), end(x) constexpr int INF = (1 << 30) - 1; constexpr long long IINF = (1LL << 60) - 1; constexpr int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1}; template istream& operator>>(istream& is, vector& v) { for (auto& x : v) is >> x; return is; } template ostream& operator<<(ostream& os, const vector& v) { auto sep = ""; for (const auto& x : v) os << exchange(sep, " ") << x; return os; } template bool chmin(T& x, U&& y) { return y < x and (x = forward(y), true); } template bool chmax(T& x, U&& y) { return x < y and (x = forward(y), true); } template void mkuni(vector& v) { sort(begin(v), end(v)); v.erase(unique(begin(v), end(v)), end(v)); } template int lwb(const vector& v, const T& x) { return lower_bound(begin(v), end(v), x) - begin(v); } using mint = atcoder::modint998244353; mint f(int n) { return mint(n) * (n + 1) / 2; } void solve() { int n; cin >> n; vector> G(n); for (int i = 0; i < n - 1; i++) { int u, v; cin >> u >> v; u--, v--; G[u].emplace_back(v); G[v].emplace_back(u); } mint ans = 0; vector sub(n); vector sq(n), prob(n); // v が白く残る確率 mint tot = f(n); auto dfs = [&](auto self, int v, int p) -> void { sub[v] = 1; mint sum = 0; sq[v] = 0; for (int& u : G[v]) { if (u == p) continue; self(self, u, v); sub[v] += sub[u]; sum += f(sub[u]); sq[v] += f(sub[u]); } sum += f(n - sub[v]); prob[v] = (tot - sum) / tot; debug(v, prob[v].val()); ans += (1 - prob[v]).inv(); for (int& u : G[v]) { if (u == p) continue; mint prob2 = 1; prob2 -= 1 - prob[v]; prob2 -= 1 - prob[u]; mint SUM = sum; SUM -= f(sub[u]); SUM += sq[u]; SUM /= tot; prob2 += SUM; ans -= (1 - prob2).inv(); debug(v, u, prob2.val()); } }; dfs(dfs, 0, -1); cout << ans.val() << '\n'; } int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int T; cin >> T; for (; T--;) solve(); return 0; }