#include <bits/stdc++.h>
using namespace std;
using lint = long long;
const int MAXN = 2e5 + 5;
const lint INF = 1e18;
int N;
vector<pair<int, int>> adj[MAXN];
lint dp[MAXN];
multiset<lint> mx[MAXN];
long long ans = 0;
void Dfs(int u, int p = -1) {
dp[u] = 0;
mx[u].emplace(-INF);
for (auto e : adj[u]) if (e.first != p) {
int v = e.first;
int w = e.second;
Dfs(v, u);
dp[u] += max(dp[v], w + dp[v] + *prev(end(mx[v])));
mx[u].emplace(dp[v] + w - max(dp[v], w + dp[v] + *prev(end(mx[v]))));
}
}
void Reroot(int u, int p = -1) {
ans = max(ans, dp[u]);
for (auto e : adj[u]) if (e.first != p) {
int v = e.first;
int w = e.second;
dp[u] -= max(dp[v], w + dp[v] + *prev(end(mx[v])));
mx[u].erase(mx[u].find(dp[v] + w - max(dp[v], w + dp[v] + *prev(end(mx[v])))));
dp[v] += max(dp[u], w + dp[u] + *prev(end(mx[u])));
mx[v].emplace(dp[u] + w - max(dp[u], w + dp[u] + *prev(end(mx[u]))));
Reroot(v, u);
dp[v] -= max(dp[u], w + dp[u] + *prev(end(mx[u])));
mx[v].erase(mx[v].find(dp[u] + w - max(dp[u], w + dp[u] + *prev(end(mx[u])))));
dp[u] += max(dp[v], w + dp[v] + *prev(end(mx[v])));
mx[u].emplace(dp[v] + w - max(dp[v], w + dp[v] + *prev(end(mx[v]))));
}
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0), cout.tie(0);
cin >> N;
for (int i = 0; i + 1 < N; i++) {
int u, v, w;
cin >> u >> v >> w;
u--, v--;
adj[u].emplace_back(v, w);
adj[v].emplace_back(u, w);
}
Dfs(0), Reroot(0);
cout << ans << "\n";
return 0;
}
