#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) (int)a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x,y) ((x+y-1)/(y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl
#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)
template<typename T>
void amin(T &a, T b) {
a = min(a,b);
}
template<typename T>
void amax(T &a, T b) {
a = max(a,b);
}
#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif
/*
read some solution ideas, found them non-intuitive
trying to build upon my previous idea
*/
const int MOD = 1e9 + 7;
const int N = 2e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;
struct S : vector<int>{
int shift = 0;
int operator[](int i){
return at(i)+shift;
}
void point_set(int i, int v){
at(i) = v-shift;
}
void point_add(int i, int v){
at(i) += v;
}
void do_shift(int x){
shift += x;
}
};
template<typename T>
struct two_max{
array<T,2> ar;
two_max(){
ar.fill(T{-inf1,-inf1});
}
void insert(T px){
if(px > ar[0]){
ar[1] = ar[0];
ar[0] = px;
}
else{
amax(ar[1],px);
}
}
};
vector<pii> adj[N];
S dp[N];
vector<int> best(N,-inf1);
void dfs1(ll u, ll p){
for(auto [v,w] : adj[u]){
if(v == p) conts;
dfs1(v,u);
}
dp[u].point_set(0,0);
int sum = 0;
rep(i,sz(adj[u])){
auto [v,w] = adj[u][i];
if(v == p) conts;
int curr_val = max(w+best[v],dp[v][0]);
sum += curr_val;
dp[u].point_set(i+1,-curr_val);
}
rep(i,sz(adj[u])+1){
dp[u].point_add(i,sum);
}
best[u] = -inf1;
rep(j,sz(adj[u])){
auto [v,w] = adj[u][j];
if(v == p) conts;
amax(best[u],w+dp[u][j+1]+dp[v][0]);
}
}
int ans = 0;
void dfs2(int u, int p){
amax(ans,dp[u][0]);
two_max<pii> vals;
rep(j,sz(adj[u])){
auto [v2,w2] = adj[u][j];
int val = w2+dp[u][j+1]+dp[v2][0];
vals.insert({val,v2});
}
rep(i,sz(adj[u])){
auto [v,w] = adj[u][i];
if(v == p) conts;
int id = -1;
rep(j,sz(adj[v])){
auto [v2,w2] = adj[v][j];
if(v2 == u){
id = j+1;
break;
}
}
int contrib = max(w+best[v],dp[v][0]);
dp[u].point_add(i+1,contrib);
dp[u].do_shift(-contrib);
int add = 0;
rep(j,2){
auto [val,v2] = vals.ar[j];
if(v2 == v) conts;
amax(add,w+val-contrib);
}
// rep(j,sz(adj[u])){
// if(j == i) conts;
// auto [v2,w2] = adj[u][j];
// int val = w+w2+dp[u][j+1]+dp[v2][0];
// amax(add,val);
// }
amax(add,dp[u][0]);
dp[v].point_add(id,-add);
rep(j,sz(adj[v])+1){
dp[v].point_add(j,add);
}
dfs2(v,u);
dp[u].do_shift(contrib);
dp[u].point_add(i+1,-contrib);
rep(j,sz(adj[v])+1){
dp[v].point_add(j,-add);
}
dp[v].point_add(id,add);
}
}
void solve(int test_case)
{
int n; cin >> n;
rep1(i,n-1){
int u,v,c; cin >> u >> v >> c;
adj[u].pb({v,c}), adj[v].pb({u,c});
}
rep1(u,n){
dp[u].resize(sz(adj[u])+1);
}
dfs1(1,-1);
dfs2(1,-1);
cout << ans << endl;
// int oans = 0;
// rep1(i,n){
// dfs1(i,-1);
// amax(oans,dp[i][0]);
// debug(dp[i][0]);
// }
// assert(ans == oans);
}
int main()
{
fastio;
int t = 1;
// cin >> t;
rep1(i, t) {
solve(i);
}
return 0;
}
