/*************************************
* author: marvinthang *
* created: 27.11.2023 20:59:10 *
*************************************/
#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define left ___left
#define right ___right
#define TIME (1.0 * clock() / CLOCKS_PER_SEC)
#define MASK(i) (1LL << (i))
#define BIT(x, i) ((x) >> (i) & 1)
#define __builtin_popcount __builtin_popcountll
#define ALL(v) (v).begin(), (v).end()
#define REP(i, n) for (int i = 0, _n = (n); i < _n; ++i)
#define REPD(i, n) for (int i = (n); i-- > 0; )
#define FOR(i, a, b) for (int i = (a), _b = (b); i < _b; ++i)
#define FORD(i, b, a) for (int i = (b), _a = (a); --i >= _a; )
#define FORE(i, a, b) for (int i = (a), _b = (b); i <= _b; ++i)
#define FORDE(i, b, a) for (int i = (b), _a = (a); i >= _a; --i)
#define scan_op(...) istream & operator >> (istream &in, __VA_ARGS__ &u)
#define print_op(...) ostream & operator << (ostream &out, const __VA_ARGS__ &u)
#ifdef LOCAL
#include "debug.h"
#else
#define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
#define DB(...) 23
#define db(...) 23
#define debug(...) 23
#endif
template <class U, class V> scan_op(pair <U, V>) { return in >> u.first >> u.second; }
template <class T> scan_op(vector <T>) { for (size_t i = 0; i < u.size(); ++i) in >> u[i]; return in; }
template <class U, class V> print_op(pair <U, V>) { return out << '(' << u.first << ", " << u.second << ')'; }
template <size_t i, class T> ostream & print_tuple_utils(ostream &out, const T &tup) { if constexpr(i == tuple_size<T>::value) return out << ")"; else return print_tuple_utils<i + 1, T>(out << (i ? ", " : "(") << get<i>(tup), tup); }
template <class ...U> print_op(tuple<U...>) { return print_tuple_utils<0, tuple<U...>>(out, u); }
template <class Con, class = decltype(begin(declval<Con>()))> typename enable_if <!is_same<Con, string>::value, ostream&>::type operator << (ostream &out, const Con &con) { out << '{'; for (__typeof(con.begin()) it = con.begin(); it != con.end(); ++it) out << (it == con.begin() ? "" : ", ") << *it; return out << '}'; }
template <class A, class B> bool minimize(A &a, B b) { if (a > b) { a = b; return true; } return false; }
template <class A, class B> bool maximize(A &a, B b) { if (a < b) { a = b; return true; } return false; }
inline char gc() { // like getchar()
static char buf[1 << 16];
static size_t bc, be;
if (bc >= be) {
buf[0] = 0, bc = 0;
be = fread(buf, 1, sizeof(buf), stdin);
}
return buf[bc++]; // returns 0 on EOF
}
int readInt() {
int a, c;
while ((a = gc()) < 40);
if (a == '-') return -readInt();
while ((c = gc()) >= 48) a = a * 10 + c - 480;
return a - 48;
}
// end of template
const int INF = 1e9 + 7;
void process(void) {
int n = readInt();
vector <vector <pair <int, int>>> adj(n);
REP(i, n - 1) {
int u = readInt() - 1, v = readInt() - 1, w = readInt();
adj[u].emplace_back(w, v);
adj[v].emplace_back(w, u);
}
vector <array <array <int, 2>, 2>> dp(n);
function<void(int)> dfs = [&] (int u) {
REP(a, 2) REP(b, 2) if (a || b) dp[u][a][b] = -INF;
for (auto [w, v]: adj[u]) {
adj[v].erase(find(ALL(adj[v]), pair {w, u}));
dfs(v);
REP(b, 2) dp[v][1][b] += w;
dp[u][0][0] += max(dp[v][0][0], dp[v][1][0]);
}
pair <int, int> best_child(-INF, -INF);
for (auto [w, v]: adj[u]) {
int cur = max(dp[v][0][0], dp[v][0][1]) - max(dp[v][0][0], dp[v][1][0]) + w;
if (best_child.fi < cur) best_child.se = best_child.fi, best_child.fi = cur;
else maximize(best_child.se, cur);
}
for (auto [w, v]: adj[u]) {
maximize(dp[u][0][1], dp[v][0][0] - max(dp[v][0][0], dp[v][1][0]) + w + (max(dp[v][0][0], dp[v][0][1]) - max(dp[v][0][0], dp[v][1][0]) + w == best_child.fi ? best_child.se : best_child.fi) + dp[u][0][0]);
}
for (auto [w, v]: adj[u]) {
maximize(dp[u][0][1], max(dp[v][0][1], dp[v][1][1]) + dp[u][0][0] - max(dp[v][0][0], dp[v][1][0]));
REP(b, 2) maximize(dp[u][1][b], dp[v][0][b] + w + dp[u][0][0] - max(dp[v][0][0], dp[v][1][0]));
}
};
dfs(0);
cout << max(dp[0][0][0], dp[0][0][1]) << '\n';
}
int main(void) {
ios_base::sync_with_stdio(false); cin.tie(nullptr); // cout.tie(nullptr);
file("beads");
// int t; cin >> t; while (t--)
process();
// cerr << "Time elapsed: " << TIME << " s.\n";
return (0^0);
}
