#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 2e5 + 5;
const int INF = 1e9 + 7;
int N;
int ans;
vector <pair <int, int>> graph[MAX_N];
int dp[MAX_N][2], pdp[MAX_N];
void dfs(int u, int p) {
dp[u][1] = -INF;
for(auto [v, w] : graph[u]) {
if(v == p) {
continue;
}
dfs(v, u);
dp[u][0] += max(dp[v][0], dp[v][1] + w);
}
for(auto [v, w] : graph[u]) {
if(v == p) {
continue;
}
dp[u][1] = max(dp[u][1], dp[u][0] - max(dp[v][0], dp[v][1] + w) + dp[v][0] + w);
}
}
void dfs2(int u, int p, int pw) {
ans = max(ans, dp[u][0] + pdp[u]);
multiset <int> siblings;
for(auto [v, w] : graph[u]) {
if(v == p) {
continue;
}
siblings.insert(dp[v][0] + w - max(dp[v][0], dp[v][1] + w));
pdp[v] = max(pdp[v], dp[u][0] - max(dp[v][0], dp[v][1] + w) + pdp[u]);
if(p != -1) {
pdp[v] = max(pdp[v], w + pw + dp[u][0] - max(dp[v][0], dp[v][1] + w) + pdp[p] + dp[p][0] - max(dp[u][0], dp[u][1] + pw));
}
}
if(siblings.size() > 1) {
for(auto [v, w] : graph[u]) {
if(v == p) {
continue;
}
siblings.erase(siblings.lower_bound(dp[v][0] + w - max(dp[v][0], dp[v][1] + w)));
pdp[v] = max(pdp[v], pdp[u] + dp[u][0] + w - max(dp[v][0], dp[v][1] + w) + *siblings.rbegin());
siblings.insert(dp[v][0] + w - max(dp[v][0], dp[v][1] + w));
}
}
for(auto [v, w] : graph[u]) {
if(v != p) {
dfs2(v, u, w);
}
}
}
int main() {
cin.tie(nullptr)->sync_with_stdio(false);
cin >> N;
for(int i = 1; i <= N - 1; i++) {
int a, b, c;
cin >> a >> b >> c;
graph[a].emplace_back(b, c);
graph[b].emplace_back(a, c);
}
dfs(1, -1);
dfs2(1, -1, -INF);
cout << ans;
return 0;
}
