#include <bits/stdc++.h>
using namespace std;
#define int long long
#define double long double
#define all(x) x.begin(), x.end()
#define f first
#define s second
#define pi pair<int, int>
string abc = "abcdefghijklmnopqrstuvwxyz";
const int N = 2e5+7;
vector<pair<int, int>> adj[N];
int dp[2][N];
void dfs(int u, int p, int sz){
// cout << "st " << u << " " << p << " " << sz << endl;
if(u != 1 && adj[u].size() == 1){
dp[1][u] = dp[0][u] = 0;
return;
}
dp[1][u] = dp[0][u]=0;
vector<pair<int, int>> v;
// cout << "st dfs" << endl;
// cout << adj[u].size() << endl;
for(auto x : adj[u]){
if(x.f != p){
// cout << "ad " << u << " " << x.f << endl;
dfs(x.f, u, x.s);
dp[0][u]+=max(dp[1][x.f], dp[0][x.f]);
v.push_back({x.s-dp[1][x.f]+dp[0][x.f], max(dp[1][x.f], dp[0][x.f])});
// cout << "ed " << u << " " << x.f << endl;
}
}
// cout << "en dfs" << endl;
if(v.size() == 0){
dp[1][u]=dp[0][u];
return;
}
sort(v.rbegin(), v.rend());
int mx = 0;
if(v.size() > 1) mx = v[0].f+v[1].f;
if(v.size() > 0) dp[1][u]=max(dp[0][u], dp[0][u]+v[0].f+sz);
else dp[1][u]=dp[0][u];
//checkear esto
if(mx > 0){
dp[0][u]+=mx;
}
// cout << "en " << u << endl;
return;
}
void solve(){
int n;
cin >> n;
for(int i = 1; i < n; i++){
int a, b, c;
cin >> a >> b >> c;
adj[a].push_back({b, c});
adj[b].push_back({a, c});
}
if(n == 1 || n == 2){
cout << 0 << endl;
return;
}
dfs(1, -1, 0);
cout << dp[0][1] << endl;
// for(int i = 0; i <= n; i++){
// cout << i << " " << dp[0][i] << " " << dp[1][i] << endl;
// }
}
signed main() {
// ios::sync_with_stdio(false); cin.tie(nullptr);
int t = 1;
// cin >> t;
while(t--){
solve();
}
}
