#include <bits/stdc++.h>
template <class T>
using Vec = std::vector<T>;
template <class F>
struct RecLambda: private F {
explicit RecLambda(F &&f): F(std::forward<F>(f)) { }
template <class... Args>
decltype(auto) operator () (Args&&... args) const {
return F::operator()(*this, std::forward<Args>(args)...);
}
};
int main() {
int N;
std::cin >> N;
Vec<Vec<std::pair<int, int>>> graph(N);
for (int i = 1; i < N; ++i) {
int a, b, c;
std::cin >> a >> b >> c;
a -= 1;
b -= 1;
graph[a].emplace_back(b, c);
graph[b].emplace_back(a, c);
}
Vec<int> t1(N), t2(N);
const auto dfs = RecLambda([&](const auto dfs, const int u, const int p) -> void {
Vec<int> a, b;
for (const auto [v, c]: graph[u]) {
if (v == p) {
continue;
}
dfs(v, u);
a.push_back(t1[v] + c);
b.push_back(std::max(t1[v], t2[v] + c));
}
t1[u] = std::accumulate(b.begin(), b.end(), 0);
t2[u] = std::numeric_limits<int>::min();
for (int i = 0; i < (int) a.size(); ++i) {
t2[u] = std::max(t2[u], t1[u] - b[i] + a[i]);
}
});
int ans = 0;
for (int i = 0; i < N; ++i) {
dfs(i, -1);
ans = std::max(ans, t1[i]);
}
std::cout << ans << '\n';
return 0;
}
