#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 210000;
const int INF = (int)(1e18);
int dp[N][2], n, a[N], b[N], c[N], ans;
vector<array<int, 2>> g[N];
void build(int v, int p = -1, int pw = 0) {
for (auto [u, w] : g[v]) if (u != p) {
build(u, v, w);
dp[v][0] += dp[u][1];
}
dp[v][1] = -INF;
for (auto [u, w] : g[v]) if (u != p)
dp[v][1] = max(dp[v][1], dp[v][0] - dp[u][1] + dp[u][0] + w);
dp[v][1] = max(dp[v][1] + pw, dp[v][0]);
}
void solve(int v, int p = -1) {
int dp0 = 0;
for (auto [u, w] : g[v])
dp0 += dp[u][1];
int m = g[v].size();
vector<int> dp1(m, -INF);
int val = -INF;
for (int i = 0; i < m; i++) {
dp1[i] = max(dp1[i], val);
auto [u, w] = g[v][i];
val = max(val, dp0 - dp[u][1] + dp[u][0] + w);
}
val = -INF;
for (int i = m - 1; i >= 0; i--) {
dp1[i] = max(dp1[i], val);
auto [u, w] = g[v][i];
val = max(val, dp0 - dp[u][1] + dp[u][0] + w);
}
for (int i = 0; i < m; i++) {
auto [u, w] = g[v][i];
dp[v][0] = dp0 - dp[u][1];
dp[v][1] = max(dp1[i] - dp[u][1] + w, dp0 - dp[u][1]);
if (u != p) solve(u, v);
}
ans = max(ans, dp0);
}
int32_t main() {
ios::sync_with_stdio(0); cin.tie(0);
cin >> n;
for (int i = 1; i <= n - 1; i++) {
cin >> a[i] >> b[i] >> c[i];
g[a[i]].push_back({b[i], c[i]});
g[b[i]].push_back({a[i], c[i]});
}
build(1);
solve(1);
cout << ans;
}
