#include <bits/stdc++.h>
#define I64 long long
using namespace std;
const int N = (int) 2E5;
const I64 A = 0 - (I64) 1E18;
int n;
vector<pair<int, int>> e[N];
int p[N];
I64 f[N][2];
I64 g[N][2];
vector<I64> a[N], b[N];
void DFS1(int u) {
if (p[u] >= 0) {
auto i = e[u].begin();
while (i -> first != p[u]) {
i = next(i);
}
e[u].erase(i);
}
f[u][0] = 0;
f[u][1] = A;
for (auto [v, x] : e[u]) {
p[v] = u;
DFS1(v);
f[u][0] = f[u][0] + max(f[v][0], f[v][1] + x);
f[u][1] = max(f[u][1], f[v][0] + x - max(f[v][0], f[v][1] + x));
}
f[u][1] = f[u][1] + f[u][0];
}
void DFS2(int u) {
int m = (int) e[u].size();
I64 s = 0;
a[u] = vector<I64>(m);
b[u] = vector<I64>(m);
for (auto [v, x] : e[u]) {
s = s + max(f[v][0], f[v][1] + x);
}
for (int i = 0; i < m; i++) {
int v, x;
tie(v, x) = e[u][i];
a[u][i] = f[v][0] + x - max(f[v][0], f[v][1] + x);
b[u][i] = f[v][0] + x - max(f[v][0], f[v][1] + x);
}
for (int i = 0; i < m - 1; i++) {
a[u][i + 1] = max(a[u][i + 1], a[u][i]);
}
for (int i = m - 1; i > 0; i--) {
b[u][i - 1] = max(b[u][i - 1], b[u][i]);
}
for (int i = 0; i < m; i++) {
int v, x;
tie(v, x) = e[u][i];
I64 t[2];
t[0] = g[u][0] + s;
t[0] = t[0] - max(f[v][0], f[v][1] + x);
t[1] = g[u][1] - g[u][0];
if (i > 0) {
t[1] = max(t[1], a[u][i - 1]);
}
if (i < m - 1) {
t[1] = max(t[1], b[u][i + 1]);
}
t[1] = t[1] + t[0];
g[v][0] = max(t[0], t[1] + x);
g[v][1] = t[0] + x;
DFS2(v);
}
}
void solve() {
cin >> n;
for (int i = 0; i < n - 1; i++) {
int u, v;
int x;
cin >> u >> v >> x;
u = u - 1;
v = v - 1;
e[u].push_back({v, x});
e[v].push_back({u, x});
}
p[0] = 0 - 1;
DFS1(0);
g[0][0] = 0;
g[0][1] = A;
DFS2(0);
I64 x = 0;
for (int u = 0; u < n; u++) {
// cout << f[u][0] + g[u][0] << "\n";
x = max(x, f[u][0] + g[u][0]);
}
cout << x << "\n";
}
int main() {
ios::sync_with_stdio(0);
cin.tie(nullptr);
solve();
return 0;
}
