#include <bits/stdc++.h>
using namespace std;
int N;
int best[200005];
vector<pair<int, int>> adj[200005];
int DP[200005], cur[200005];
int maxW[200005][2], sum[200005];
int nDP[200005], ncur[200005];
int nsum[200005];
void dfs(int v, int p) {
maxW[v][0] = maxW[v][1] = -1e9;
for(auto u : adj[v]) {
if(u.first == p) continue;
dfs(u.first, v);
sum[u.first] = max(DP[u.first], u.second + cur[u.first]);
DP[v] += sum[u.first];
maxW[v][1] = max(maxW[v][1], u.second + DP[u.first] - sum[u.first]);
if(maxW[v][0] < maxW[v][1])
swap(maxW[v][0], maxW[v][1]);
}
cur[v] = maxW[v][0] + DP[v];
}
void solve(int v, int p, int preW, int preC) {
if(v != -1) {
nDP[v] = DP[p] - sum[v] + nsum[p];
int c = maxW[p][0];
if(preW + DP[v] - sum[v] == c)
c = maxW[p][1];
c = max(c, preC);
ncur[v] = c + nDP[v];
nsum[v] = max(nDP[v], preW + ncur[v]);
preC = preW + nDP[v] - nsum[v];
}
for(auto u : adj[v]) {
if(u.first == p) continue;
solve(u.first, v, u.second, preC);
}
}
int32_t main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
cin >> N;
for(int l = 0; l < N - 1; l++) {
int U, V, W; cin >> U >> V >> W;
adj[U].push_back({V, W});
adj[V].push_back({U, W});
}
dfs(1, 1); solve(1, -1, 0, -1e9);
int res = 0;
for(int l = 1; l <= N; l++)
res = max(res, DP[l] + nsum[l]);
cout << res << "\n";
}
