#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][2]; // dp[u][do we use parent edge?]
void Dfs(int u, int p = -1) {
dp[u][0] = dp[u][1] = 0;
lint mx = -INF;
for (auto e : adj[u]) if (e.first != p) {
int v = e.first;
int w = e.second;
Dfs(v, u);
dp[u][0] += max(dp[v][0], w + dp[v][1]);
dp[u][1] += max(dp[v][0], w + dp[v][1]);
mx = max(mx, dp[v][0] + w - max(dp[v][0], w + dp[v][1]));
}
dp[u][1] += mx;
}
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);
}
lint ans = 0;
for (int i = 0; i < N; i++) {
Dfs(i);
ans = max(ans, dp[i][0]);
}
cout << ans << "\n";
return 0;
}
