#include <bits/stdc++.h> using namespace std; typedef long long ll; const int maxn = 2e5 + 10; const int inf = 1e9; int dp[maxn], pd[maxn]; vector<pair<int, int> > t[maxn]; pair<int,int> merge(pair<int,int> twomax, int k){ if (k > twomax.second) twomax.second = k; if (twomax.first < twomax.second) swap(twomax.first, twomax.second); return twomax; } void dfs(int v, int par = -1){ int sum = 0; pair<int,int> twomax = {-inf, -inf}; for (auto edge : t[v]){ int u = edge.first, c = edge.second; if (u != par){ dfs(u, v); ll mx = max(dp[u], pd[u] + c); sum += mx; twomax = merge(twomax, dp[u] + c - mx); } } int extra = max(0, twomax.first + twomax.second); dp[v] = sum + extra; pd[v] = sum + twomax.first; } int main(){ ios_base::sync_with_stdio (false); int n; cin >> n; for (int i = 1; i <= n - 1; i++){ int v, u, c; cin >> v >> u >> c; t[v].push_back({u, c}); t[u].push_back({v, c}); } dfs(1); cout << dp[1] << endl; }