#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define sp ' '
#define en '\n'
#define smin(a, b) a = min(a, b)
#define smax(a, b) a = max(a, b)
using namespace std;
const int N = 2e5 + 2;
const int inf = 1e9;
vector<pair<int, int>> g[N];
int dp[N][2];
void Dfs(int s, int e, int val) {
vector<int> all;
int sum = 0;
for (auto z : g[s]) {
int u = z.first; int v = z.second;
if (u == e) continue;
Dfs(u, s, v);
sum += max(dp[u][0], dp[u][1]);
all.push_back(v + dp[u][0] - max(dp[u][0], dp[u][1]));
}
sort(all.rbegin(), all.rend());
dp[s][0] = sum;
if (all.size() > 0) dp[s][1] = sum + all[0] + val;
if (all.size() > 1) smax(dp[s][0], sum + all[0] + all[1]);
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int n; cin >> n;
for (int i = 0; i < n - 1; i++) {
int u, v, w;
cin >> u >> v >> w;
g[u].push_back({v, w});
g[v].push_back({u, w});
}
Dfs(1, 0, 0);
cout << dp[1][0] << en;
return 0;
}
