#include <iostream>
#include <vector>
using namespace std;
const int MAXN = 2e5 + 123;
const int INF = 1.77013e9;
vector<pair<int, int>> edg[MAXN];
int dp[MAXN][2];
void update(int v, int rt) {
dp[v][0] = dp[v][1] = 0;
int rtw = -INF;
for (auto [u, w] : edg[v]) {
if (u == rt) {
rtw = w;
continue;
}
dp[v][0] += max(dp[u][0], dp[u][1]);
}
dp[v][1] = dp[v][0];
if (rtw != -INF) {
for (auto [u, w] : edg[v]) {
if (u == rt)
continue;
dp[v][1] = max(dp[v][1], dp[v][0] + rtw + w + min(0, dp[u][0] - dp[u][1]));
}
}
}
void get_ans(int v, int rt) {
for (auto [u, w] : edg[v]) {
if (u == rt) {
continue;
}
get_ans(u, v);
}
update(v, rt);
}
int dfs(int v, int rt) {
int ans = dp[v][0];
for (auto [u, w] : edg[v]) {
if (u == rt)
continue;
update(v, u);
update(u, -1);
ans = max(ans, dfs(u, v));
update(u, v);
update(v, -1);
}
return ans;
}
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
int n;
cin >> n;
for (int i = 0; i < n - 1; ++i) {
int u, v, d;
cin >> u >> v >> d;
--u, --v;
edg[u].push_back({v, d});
edg[v].push_back({u, d});
}
get_ans(0, -1);
int ans = dfs(0, -1);
cout << ans << endl;
}
