#include <iostream>
#include <vector>
using namespace std;
const int MAXN = 2e5 + 123;
const int INF = 1.77013e9;
vector<pair<int, int>> edg[MAXN];
int dp0[MAXN];
int dp1[MAXN];
void update(int v, int rt) {
dp0[v] = dp1[v] = 0;
int rtw = -INF;
for (auto [u, w] : edg[v]) {
if (u == rt) {
rtw = w;
continue;
}
dp0[v] += max(dp0[u], dp1[u]);
}
dp1[v] = dp0[v];
if (rtw != -INF) {
for (auto [u, w] : edg[v]) {
if (u == rt)
continue;
dp1[v] = max(dp1[v], dp0[v] + rtw + w + min(0, dp0[u] - dp1[u]));
}
}
}
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 dpv0 = dp0[v];
int dpv1 = dp1[v];
int ans = dp0[v];
int a0 = -INF;
int a1 = -INF;
for (auto [u, w] : edg[v]) {
int x = w + min(0, dp0[u] - dp1[u]);
if (x > a0) {
a1 = a0;
a0 = x;
} else if (x > a1) {
a1 = x;
}
}
for (auto [u, w] : edg[v]) {
if (u == rt)
continue;
int dpu0 = dp0[u];
int dpu1 = dp1[u];
dp0[v] -= max(dp0[u], dp1[u]);
dp1[v] = dp0[v];
int x = w + min(0, dp0[u] - dp1[u]);
if (x == a0) {
if (a1 != -INF)
dp1[v] = max(dp1[v], dp0[v] + w + a1);
} else if (a0 != -INF) {
dp1[v] = max(dp1[v], dp0[v] + w + a0);
}
update(u, -1);
ans = max(ans, dfs(u, v));
dp0[v] = dpv0;
dp1[v] = dpv1;
dp0[u] = dpu0;
dp1[u] = dpu1;
}
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 << '\n';
}
