#include <bits/stdc++.h>
using namespace std;
using vint = vector<int>;
using ll = long long;
using vll = vector<ll>;
using pint = pair<int, int>;
using vpint = vector<pint>;
using pll = pair<ll, ll>;
using vpll = vector<pll>;
using pill = pair<int, ll>;
using vpill = vector<pill>;
using plli = pair<ll, int>;
using vplli = vector<plli>;
#define e1 first
#define e2 second
#define all(x) begin(x), end(x)
const int INF = 1e9;
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n; cin >> n;
vint a(n-1), b(n-1), c(n-1);
for (int i = 0; i < n-1; i++) cin >> a[i] >> b[i] >> c[i];
vector<vpint> adj(n);
for (int i = 0; i < n-1; i++)
adj[a[i]-1].push_back({b[i]-1, c[i]}), adj[b[i]-1].push_back({a[i]-1, c[i]});
vint p(n, -1); p[0] = 0;
vint order; order.reserve(n);
queue<int> bfs_qu;
bfs_qu.push(0);
while (!bfs_qu.empty()) {
int v = bfs_qu.front(); bfs_qu.pop();
order.push_back(v);
for (auto& [ad, w] : adj[v]) if (p[ad] == -1) {
p[ad] = v; bfs_qu.push(ad);
}
}
reverse(all(order));
vint size(n);
for (auto& i : order) {
int si = 1;
for (auto& [ad, w]: adj[i]) if (ad != p[i]) si += size[ad];
size[i] = si;
}
vint dp_ts_po(n), dp_ts_no(n);
vint dp_po(n), dp_no(n);
for (auto& i : order) {
vint no_val; int no_res;
if (size[i] == 1) dp_no[i] = 0;
else {
for (auto& [ad, w]: adj[i]) if (ad != p[i]) {
int c_val = dp_no[ad];
if (size[ad] > 1) c_val = max(c_val, w + dp_po[ad]);
no_val.push_back(c_val);
}
no_res = accumulate(all(no_val), 0);
dp_no[i] = no_res;
}
if (size[i] == 1) dp_po[i] = INF;
else {
vint po_val;
for (auto& [ad, w]: adj[i]) if (ad != p[i]) {
int c_val = w + dp_no[ad];
po_val.push_back(c_val);
}
int max_diff = -INF;
for (int j = 0; j < (int)po_val.size(); j++)
max_diff = max(max_diff, po_val[j] - no_val[j]);
int po_res = no_res + max_diff;
dp_po[i] = po_res;
}
if (size[i] == 1) dp_ts_no[i] = 0;
else {
vint ts_no_val_1;
for (auto& [ad, w]: adj[i]) if (ad != p[i]) {
int c_val = 0;
if (size[ad] > 1) c_val = max(c_val, w + dp_ts_po[ad]);
ts_no_val_1.push_back(c_val);
}
int max_diff_1 = -INF;
for (int j = 0; j < (int)ts_no_val_1.size(); j++)
max_diff_1 = max(max_diff_1, ts_no_val_1[j] - no_val[j]);
int ts_no_res_1 = no_res + max_diff_1;
vint ts_no_val_2;
for (auto& [ad, w]: adj[i]) if (ad != p[i]) {
int c_val = dp_ts_no[ad];
ts_no_val_2.push_back(c_val);
}
int max_diff_2 = -INF;
for (int j = 0; j < (int)ts_no_val_2.size(); j++)
max_diff_2 = max(max_diff_2, ts_no_val_2[j] - no_val[j]);
int ts_no_res_2 = no_res + max_diff_2;
int ts_no_res_3 = 0;
if (no_val.size() > 1) {
vint diff_vals;
int j = 0;
for (auto& [ad, w]: adj[i]) if (ad != p[i]) {
int c_val = w + dp_no[ad];
diff_vals.push_back(c_val - no_val[j]);
j++;
}
vint diff_vals_sorted(diff_vals); sort(all(diff_vals_sorted), greater<>());
vint ts_no_res_val_3;
j = 0;
for (auto& [ad, w]: adj[i]) if (ad != p[i]) {
int c_val = w + dp_ts_no[ad];
int c_diff = c_val - no_val[j];
int idx = 0; if (diff_vals_sorted[idx] == diff_vals[j]) idx++;
int c_res = no_res + diff_vals_sorted[idx] + c_diff;
ts_no_res_val_3.push_back(c_res);
j++;
}
ts_no_res_3 = *max_element(all(ts_no_res_val_3));
}
dp_ts_no[i] = max({ts_no_res_1, ts_no_res_2, ts_no_res_3});
}
if (size[i] == 1) dp_ts_po[i] = INF;
else {
vint ts_po_val;
for (auto& [ad, w]: adj[i]) if (ad != p[i]) {
int c_val = w + dp_ts_no[ad];
ts_po_val.push_back(c_val);
}
int max_diff = -INF;
for (int j = 0; j < (int)ts_po_val.size(); j++)
max_diff = max(max_diff, ts_po_val[j] - no_val[j]);
int ts_po_res = no_res + max_diff;
dp_ts_po[i] = ts_po_res;
}
}
cout << dp_ts_no[0] << endl;
return 0;
}
