#ifndef HIDDEN_IN_VS // 折りたたみ用

#include <bits/stdc++.h>

using namespace std;
// 型名の短縮
using ll = long long; using ull = unsigned long long; // -2^63 ～ 2^63 = 9 * 10^18（int は -2^31 ～ 2^31 = 2 * 10^9）
using pii = pair<int, int>;	using pll = pair<ll, ll>;	using pil = pair<int, ll>;	using pli = pair<ll, int>;
using vi = vector<int>;		using vvi = vector<vi>;		using vvvi = vector<vvi>;	using vvvvi = vector<vvvi>;
using vl = vector<ll>;		using vvl = vector<vl>;		using vvvl = vector<vvl>;	using vvvvl = vector<vvvl>;
using vb = vector<bool>;	using vvb = vector<vb>;		using vvvb = vector<vvb>;
using vc = vector<char>;	using vvc = vector<vc>;		using vvvc = vector<vvc>;
using vd = vector<double>;	using vvd = vector<vd>;		using vvvd = vector<vvd>;

template <class T> using priority_queue_rev = priority_queue<T, vector<T>, greater<T>>;
template <typename T> bool chmax(T &m, const T q) { if (m < q) {m = q; return true;} else return false; }
template <typename T> bool chmin(T &m, const T q) { if (m > q) {m = q; return true;} else return false; }

#define all(a) a.begin(),a.end()
#define rep(i, n) for(int i = 0, i##_end = int(n); i < i##_end; ++i) // 0 から n-1 まで昇順
#define repi(i, s, t) for(int i = int(s), i##_end = int(t); i <= i##_end; ++i) // s から t まで昇順
#define repir(i, s, t) for(int i = int(s), i##_end = int(t); i >= i##_end; --i) // s から t まで降順
#define repe(v, a) for(const auto& v : (a)) // a の全要素（変更不可能）
#define repea(v, a) for(auto& v : (a)) // a の全要素（変更可能）
#define repb(set, d) for(int set = 0; set < (1 << int(d)); ++set) // d ビット全探索（昇順）
#define repp(a) sort(all(a)); for(bool a##_perm = true; a##_perm; a##_perm = next_permutation(all(a))) // a の順列全て（昇順）
#define smod(n, m) ((((n) % (m)) + (m)) % (m)) // 非負mod
#define uniq(a) {sort(all(a)); (a).erase(unique(all(a)), (a).end());} // 重複除去
// template <class T> inline T smod(T n, T m) { n %= m; if (n < 0) n += m; return n; } // 非負mod

long long TEN(int x) { return x == 0 ? 1 : TEN(x - 1) * 10; }
#include <atcoder/all>
using namespace atcoder;
// using mint = modint998244353;
#endif



#ifdef local_mode
#include "local.hpp"
#else
#define dump(...)
#define dumpel(v)
#endif

struct fast_io { fast_io() { cin.tie(nullptr); ios::sync_with_stdio(false); } } fastIOtmp;


int main(){
	int n;
	cin >> n;
	vector<vector<pair<int,ll>>> G(n);
	// vvi I(n);
	rep(i,n-1){
		int u,v;
		ll w;
		cin >> u >> v >> w;
		u--;v--;
		G[u].push_back({v,w});
		G[v].push_back({u,w});
		
	}
	dumpel(G);
	vvl dp(n);
	rep(i,n) dp[i].resize(G[i].size());

	vi IDX(n,-1);

	function<void(int,int,int)> dfs = [&](int u, int p, int idx){
		bool is_leaf = true;
		ll rw;
		rw=0;
		rep(i,G[u].size()){
			auto[v,w] = G[u][i];
			if(v==p){
				IDX[u]=i;
				continue;
			}
			is_leaf = false;
			dfs(v,u,i); 
			chmax(rw,dp[u][i]+w);
		}

		if(p!=-1)dp[p][idx]=rw;
		return;
	};

	dfs(0,-1,-1);
	ll inf = 4004004004004004004;
	dump("IDX:",IDX);
	vl dp2(n);

	function<void(int,int)> dfs2 = [&](int u, int p){		
		// int idx = -1;
		dump(u);
		vl V;
		rep(i,G[u].size()){
			auto[v,w] = G[u][i];
			// if(v==p){
				// idx = i;
				// V.push_back(-inf);
				// continue;
			// }
			V.push_back(dp[u][i]+w);
		}
		dump(V);
		int m = V.size();
		vl L(m+1,-inf),R(m+1,-inf);
		rep(i,m){
			L[i+1] = max(L[i],V[i]);
			R[m-1-i] = max(R[m-i],V[m-1-i]);
		}
		dp2[u]=R[0];
		vl M(m);
		rep(i,m){
			M[i] = max(L[i],R[i+1]);
		}
		dump("M:",M);
		rep(i,G[u].size()){
			auto[v,w] = G[u][i];
			if(v==p)continue;
			dp[v][IDX[v]]=M[i];
			dfs2(v,u);
		}
		
		return;
	};

	dfs2(0,-1);
	dumpel(dp);

	cout << *max_element(all(dp2)) << endl;

}