#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 2e5 + 10;
const int inf = 1e13;
int n, dp[N][2][2];
vector<pair<int, int>> adj[N];
void dfs(int u, int p) {
dp[u][0][1] = dp[u][1][0] = dp[u][1][1] = -inf;
vector<pair<int, int>> vec;
int non_root = 0;
for (auto& [v, w] : adj[u]) {
if (v == p) continue;
dfs(v, u);
non_root++;
dp[u][0][0] += max(dp[v][0][1] + w, dp[v][0][0]);
vec.push_back({dp[v][0][0] + w - max(dp[v][0][1] + w, dp[v][0][0]), v});
}
if (non_root == 0) return;
int sum = dp[u][0][0];
sort(vec.begin(), vec.end(), [] (auto a, auto b) { return a.first > b.first; });
dp[u][0][1] = dp[u][0][0] + vec[0].first;
for (auto& [v, w] : adj[u]) {
if (v == p) continue;
dp[u][1][1] = max(dp[u][1][1], sum + max(dp[v][0][0], dp[v][1][0]) + w - max(dp[v][0][0], dp[v][0][1] + w));
dp[u][1][0] = max(dp[u][1][0], sum + max(dp[v][1][0], dp[v][1][1] + w) - max(dp[v][0][0], dp[v][0][1] + w));
if (vec[0].second != v) dp[u][1][0] = max(dp[u][1][0], sum + max(dp[v][1][0], dp[v][0][0]) + w - max(dp[v][0][0], dp[v][0][1] + w) + vec[0].first);
else if (vec.size() > 1) dp[u][1][0] = max(dp[u][1][0], sum + max(dp[v][1][0], dp[v][0][0]) + w - max(dp[v][0][0], dp[v][0][1] + w) + vec[1].first);
}
}
int32_t main() {
ios::sync_with_stdio(0); cin.tie(0);
cin >> n;
for (int i = 1; i < n; i++) {
int u, v, w;
cin >> u >> v >> w;
adj[u].push_back({v, w});
adj[v].push_back({u, w});
}
dfs(1, -1);
cout << max(dp[1][0][0], dp[1][1][0]) << '\n';
}
/*
10
4 10 2
1 2 21
1 3 13
6 7 1
7 9 5
2 4 3
2 5 8
1 6 55
6 8 34
*/
