#include <bits/stdc++.h>
using namespace std;
#define int long long
const int INF = 1e9 + 2;
const int N = 2e5 + 5;
vector<pair<int , int> > g[N];
int dp[N][2] , n;
void dfs(int v , int p){
if((int)g[v].size() == 1 && v != 1){
dp[v][1] = -INF;
return;
}
for(auto u : g[v]){
if(u.first == p) continue;
dfs(u.first , v);
}
vector<int> vec;
int ans = 0;
for(auto u : g[v]){
if(u.first == p) continue;
int mx = max(dp[u.first][1] + u.second , dp[u.first][0]);
ans += mx;
vec.push_back(dp[u.first][0] + u.second - mx);
}
sort(vec.begin() , vec.end());
dp[v][1] = ans + vec.back();
dp[v][0] = ans;
if((int)vec.size() >= 2)
dp[v][0] = max(dp[v][0] , dp[v][1] + vec[(int)vec.size() - 2]);
}
int32_t main(){
cin >> n;
for(int i = 0 ; i < n - 1 ; i++){
int x , y , w;
cin >> x >> y >> w;
g[x].push_back({y , w});
g[y].push_back({x , w});
}
dfs(1 , 0);
cout << dp[1][0] << '\n';
return 0;
}
