#include <bits/stdc++.h>
#define fi first
#define se second
using namespace std;
typedef pair<int, int> ii;
const int N = 200005;
int n, f[N][2];
vector<ii> G[N];
void dfs(int u, int p) {
f[u][0] = 0;
for (auto v : G[u]) {
if (v.fi == p) continue;
dfs(v.fi, u);
}
int mx = -1e9;
for (auto v : G[u]) {
if (v.fi == p) continue;
int vMx = max(f[v.fi][0], f[v.fi][1] + v.se);
f[u][0] += vMx;
mx = max(mx, f[v.fi][0] + v.se - vMx);
}
f[u][1] = f[u][0] + mx;
}
int main() {
ios::sync_with_stdio(false);
cin >> n;
for (int i = 1; i < n; ++i) {
int u, v, w;
cin >> u >> v >> w;
G[u].push_back(ii(v, w));
G[v].push_back(ii(u, w));
}
int res = 0;
for (int i = 1; i <= n; ++i) {
dfs(i, i), res = max(res, f[i][0]);
}
cout << res;
}
