#include <bits/stdc++.h>
using namespace std;
const int N = 200010;
const int inf = 1e9;
int n;
int f[N][2], g[N][2];
vector < pair<int,int> > G[N], ch[N];
int ans;
void dfs(int u, int p) {
for (auto edge: G[u]) if (edge.second != p) {
dfs(edge.second, u);
ch[u].push_back(edge);
}
f[u][1] = -inf;
f[u][0] = 0;
for (auto edge: ch[u]) {
f[u][0] += max(f[edge.second][0], f[edge.second][1] + edge.first);
}
for (auto edge: ch[u]) {
int mx = f[u][0];
mx -= max(f[edge.second][0], f[edge.second][1] + edge.first);
mx += (f[edge.second][0] + edge.first);
f[u][1] = max(f[u][1], mx);
}
}
void re_dfs(int u, int p) {
ans = max(ans, g[u][0] + f[u][0]);
//cerr << "redfs " << u << ' ' << f[u][0] + g[u][0] << ' ' << f[u][1] + g[u][1] << endl;
// prepare
vector <int> L(ch[u].size() + 2, 0); L[0] = -inf;
vector <int> R(ch[u].size() + 2, 0); R[(int)ch[u].size()] = -inf;
for (int i = 0; i < (int)ch[u].size(); ++i) {
pair<int,int> edge = ch[u][i];
L[i + 1] = max(L[i], f[u][0] - max(f[edge.second][0], f[edge.second][1] + edge.first) + (f[edge.second][0] + edge.first));
}
for (int i = (int)ch[u].size() - 1; i >= 0; --i) {
pair<int,int> edge = ch[u][i];
R[i] = max(R[i + 1], f[u][0] - max(f[edge.second][0], f[edge.second][1] + edge.first) + (f[edge.second][0] + edge.first));
}
// solve
for (int i = 0; i < (int)ch[u].size(); ++i) {
int v = ch[u][i].second, w = ch[u][i].first;
int cost = max(f[v][0], f[v][1] + w);
int fu0 = f[u][0] - cost;
int mx = max(L[i], R[i + 1]);
int fu1 = mx >= 0 ? mx - cost : -inf;
g[v][0] = 0, g[v][1] = -inf;
// g[v][0]
g[v][0] = max(g[v][0], fu0 + g[u][0]);
g[v][0] = max(g[v][0], fu1 + g[u][0] + w);
g[v][0] = max(g[v][0], fu0 + g[u][1] + w);
// g[v][1]
g[v][1] = max(g[v][1], g[u][0] + fu0 + w);
re_dfs(v, u);
}
}
int main() {
ios_base::sync_with_stdio(false); cin.tie(0);
cin >> n;
for (int i = 1; i < n; ++i) {
int u, v, w; cin >> u >> v >> w;
G[u].push_back(make_pair(w,v)); G[v].push_back(make_pair(w,u));
}
dfs(1,1);
g[1][1] = -inf;
re_dfs(1,1);
cout << ans << endl;
}
