/**
	author:  shobonvip
	created: 2025.04.19 22:46:03
**/

#include<bits/stdc++.h>
using namespace std;

//* ATCODER
#include<atcoder/all>
using namespace atcoder;
typedef modint998244353 mint;
//*/

/* BOOST MULTIPRECISION
#include<boost/multiprecision/cpp_int.hpp>
using namespace boost::multiprecision;
//*/

typedef long long ll;

#define rep(i, s, n) for (int i = (int)(s); i < (int)(n); i++)
#define rrep(i, s, n) for (int i = (int)(n)-1; i >= (int)(s); i--)
#define all(v) v.begin(), v.end()

template <typename T> bool chmin(T &a, const T &b) {
	if (a <= b) return false;
	a = b;
	return true;
}

template <typename T> bool chmax(T &a, const T &b) {
	if (a >= b) return false;
	a = b;
	return true;
}

template <typename T> T max(vector<T> &a){
	assert(!a.empty());
	T ret = a[0];
	for (int i=0; i<(int)a.size(); i++) chmax(ret, a[i]);
	return ret;
}

template <typename T> T min(vector<T> &a){
	assert(!a.empty());
	T ret = a[0];
	for (int i=0; i<(int)a.size(); i++) chmin(ret, a[i]);
	return ret;
}

template <typename T> T sum(vector<T> &a){
	T ret = 0;
	for (int i=0; i<(int)a.size(); i++) ret += a[i];
	return ret;
}

int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);

	int n; cin >> n;
	vector ikeru(n, vector<pair<int,ll>>(0));
	rep(i,0,n-1) {
		int u, v; cin >> u >> v;
		u--; v--;
		ll w; cin >> w;
		ikeru[u].push_back(pair(v, w));
		ikeru[v].push_back(pair(u, w));
	}

	vector<ll> dp(n, 0);
	ll ans = 0;
	auto dfs1 = [&](auto self, int i, int p) -> void {
		for (auto [j, w]: ikeru[i]) {
			if (j == p) continue;
			self(self, j, i);
			chmax(dp[i], dp[j] + w);
		}
	};

	dfs1(dfs1, 0, -1);

	auto dfs2 = [&](auto self, int i, int p, ll val) -> void {
		vector<ll> lft = {val};
		ll now = val;
		int piv = 0;
		for (auto [j, w]: ikeru[i]) {
			if (j == p) continue;
			chmax(now, dp[j] + w);
			lft.push_back(now);
			piv++;
		}

		reverse(all(ikeru[i]));

		now = val;
		for (auto [j, w]: ikeru[i]) {
			if (j == p) continue;
			piv--;
			self(self, j, i, max(now, lft[piv]) + w);
			chmax(now, dp[j] + w);
		}
	
		reverse(all(ikeru[i]));

		chmax(ans, now);
	};

	dfs2(dfs2, 0, -1, 0);
	cout << ans << endl;

	

}