#include <bits/stdc++.h>
using namespace std;
#define ll long long
const int MOD = 1e9 + 7;
const int N = 2e5 + 2;
int ans = 0, o[N], t[N];
vector<vector<pair<int,int>>> edges(N);
void dfs1(int node, int parent) {
int val = 0;
for (auto child : edges[node]) {
if (child.first == parent) continue;
dfs1(child.first, node);
if (t[child.first] != -1) t[child.first] += child.second;
t[child.first] = max(t[child.first], o[child.first]);
o[child.first] += child.second;
val += t[child.first];
}
o[node] = val;
for (auto child : edges[node]) {
if (child.first == parent) continue;
t[node] = max(t[node], val - t[child.first] + o[child.first]);
}
}
void dfs2(int node, int parent, int o_val, int t_val) {
int val = 0, val1 = INT_MIN, val2 = INT_MIN;
if (node != 1) val += t_val, val1 = o_val - t_val;
for (auto child : edges[node]) {
if (child.first == parent) continue;
val += t[child.first];
if (val1 == INT_MIN) val1 = o[child.first] - t[child.first];
else {
val2 = max(val2, o[child.first] - t[child.first]);
if (val2 > val1) swap(val1, val2);
}
}
ans = max(ans, val + max(0, val1 + val2));
for (auto child : edges[node]) {
if (child.first == parent) continue;
val -= t[child.first];
if (o[child.first] - t[child.first] == val1) dfs2(child.first, node, val + child.second, max(val, val + val2 + child.second));
else dfs2(child.first, node, val + child.second, max(val, val + val1 + child.second));
val += t[child.first];
}
}
void solve() {
int n, a, b, c;
cin >> n;
for (int i = 1; i < n; i++) {
cin >> a >> b >> c;
edges[a].push_back(make_pair(b, c));
edges[b].push_back(make_pair(a, c));
}
for (int i = 1; i <= n; i++) o[i] = t[i] = -1;
dfs1(1, 0);
dfs2(1, 0, 0, 0);
cout << ans << "\n";
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
// #ifndef ONLINE_JUDGE
// freopen("input.in", "r", stdin);
// freopen("output.out", "w", stdout);
// #endif
ll t;
t = 1;
// cin >> t;
while(t--) {
solve();
}
return 0;
}
