#include <bits/stdc++.h>
using namespace std;
const int maxn = 2e5;
const long long inf = 1e13;
vector<pair<int, int>> g[maxn];
long long dp[maxn][2];
void dfsCalc(int v, int p) {
dp[v][0] = 0, dp[v][1] = -inf;
for (const auto& [u, w] : g[v]) {
if (u != p) {
dfsCalc(u, v);
dp[v][0] += max(dp[u][0], dp[u][1] + w);
}
}
for (const auto& [u, w] : g[v]) {
if (u != p) {
dp[v][1] = max(dp[v][1], dp[v][0] - max(dp[u][0], dp[u][1] + w) + dp[u][0] + w);
}
}
}
long long up[maxn][2];
long long dfsAns(int v, int p, int pw) {
long long ans, whole;
ans = whole = dp[v][0] + max(up[v][0], up[v][1] + pw);
pair<long long, int> max1 = {-inf, -2}, max2 = {-inf, -2}, cur;
if (p != -1) {
cur = {-max(up[v][0], up[v][1] + pw) + up[v][0] + pw, -1};
if (cur >= max1) {
max2 = max1, max1 = cur;
} else if (cur > max2) {
max2 = cur;
}
}
for (const auto& [u, w] : g[v]) {
if (u != p) {
cur = {-max(dp[u][0], dp[u][1] + w) + dp[u][0] + w, u};
if (cur >= max1) {
max2 = max1, max1 = cur;
} else if (cur > max2) {
max2 = cur;
}
}
}
for (const auto& [u, w] : g[v]) {
if (u != p) {
up[u][0] = whole - max(dp[u][0], dp[u][1] + w);
if (max1.second != u) {
up[u][1] = up[u][0] + max1.first;
} else {
up[u][1] = up[u][0] + max2.first;
}
ans = max(ans, dfsAns(u, v, w));
}
}
return ans;
}
void solve() {
int n;
cin >> n;
for (int i = 0; i < n - 1; ++i) {
int v, u, w;
cin >> v >> u >> w;
--v, --u;
g[v].emplace_back(u, w);
g[u].emplace_back(v, w);
}
dfsCalc(0, -1);
up[0][0] = up[0][1] = 0;
cout << dfsAns(0, -1, 0) << '\n';
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
#ifdef LOCAL
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
int T = 1;
cin >> T;
while (T--) {
solve();
cerr << "-----------\n";
cout << "-----------\n";
}
#else
int T = 1;
// cin >> T;
while (T--) {
solve();
}
#endif
return 0;
}
