#include <bits/stdc++.h>
#define fi first
#define se second
using namespace std;
typedef pair<int, int> ii;
const int N = 200005;
const int INF = -1e9;
int n, res;
int f[N][2], g[N][2];
int L[N], R[N];
vector<ii> G[N];
void dfs(int u, int p) {
for (auto v : G[u]) {
if (v.fi == p) continue;
dfs(v.fi, u);
}
int mx = INF;
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;
}
void reDfs(int u, int p) {
vector<ii> _G;
for (auto v : G[u]) {
if (v.fi == p) continue;
_G.push_back(v);
}
int sz = _G.size(), sum = 0;
L[0] = INF, R[sz + 1] = INF;
for (int i = 1; i <= sz; ++i) {
ii v = _G[i - 1];
sum += max(f[v.fi][0], f[v.fi][1] + v.se);
int vMx = max(f[v.fi][0], f[v.fi][1] + v.se);
L[i] = max(L[i - 1], f[v.fi][0] + v.se - vMx);
}
for (int i = sz; i >= 1; --i) {
ii v = _G[i - 1];
int vMx = max(f[v.fi][0], f[v.fi][1] + v.se);
R[i] = max(R[i + 1], f[v.fi][0] + v.se - vMx);
}
for (int i = 1; i <= sz; ++i) {
ii v = _G[i - 1];
int mx = max(L[i - 1], R[i + 1]);
int tSum = sum - max(f[v.fi][0], f[v.fi][1] + v.se);
tSum += g[u][0], mx = max(mx, g[u][1] - g[u][0]);
// f0 = tSum, f1 = tSum + mx;
g[v.fi][0] = max(tSum, tSum + mx + v.second), g[v.fi][1] = tSum + v.second;
}
//cout << u << ' ' << f[u][0] << ' ' << f[u][1] << '\n';
//cout << u << ' ' << g[u][0] << ' ' << g[u][1] << '\n';
res = max(res, f[u][0] + g[u][0]);
for (auto v : _G) reDfs(v.fi, u);
}
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));
}
dfs(1, 1);
g[1][1] = INF;
res = f[1][0];
reDfs(1, 1);
cout << res;
// int res = 0;
// for (int i = 1; i <= n; ++i) {
// dfs(i, i), res = max(res, f[i][0]);
// }
// cout << res;
}
