#include<bits/stdc++.h>
#define int long long
using namespace std;
template<class T> using matrix = vector<vector<T>>;
const int MAXN = 2e5;
const int INF = 1e15;
int n, dp[2][MAXN], ans;
pair<int, int> subs[MAXN];
matrix<pair<int, int>> G;
void dfs_dp(int u, int p){
dp[1][u] = -INF;
subs[u] = {-INF, -INF};
for(auto [v, w] : G[u]){
if(v == p) continue;
dfs_dp(v, u);
int t = max(dp[0][v], (dp[1][v] != -INF ? dp[1][v] + w : 0LL));
dp[0][u] += t;
int my_sub = (dp[0][v] + w) - t;
if(my_sub > subs[u].first){ subs[u].second = subs[u].first; subs[u].first = my_sub; }
else if(my_sub > subs[u].second){ subs[u].second = my_sub; }
}
dp[1][u] = dp[0][u] + subs[u].first;
}
void dfs_ans(int u, int p){
ans = max(dp[0][u], ans);
for(auto [v, w] : G[u]){
if(v == p) continue;
auto a = dp[0][u];
auto b = dp[1][u];
auto c = dp[0][v];
auto d = dp[1][v];
auto e = subs[u];
int tu = max(dp[0][v], (dp[1][v] != -INF ? dp[1][v] + w : 0LL));
dp[0][u] -= tu;
if((dp[0][v] + w) - tu == subs[u].first) dp[1][u] = dp[0][u] + subs[u].second;
else dp[1][u] = dp[0][u] + subs[u].first;
int tv = max(dp[0][u], (dp[1][u] != -INF ? dp[1][u] + w : 0LL));
dp[0][v] += tv;
int my_sub = (dp[0][u] + w) - tv;
if(my_sub > subs[v].first){ subs[v].second = subs[v].first; subs[v].first = my_sub; }
else if(my_sub > subs[v].second){ subs[v].second = my_sub; }
dp[1][v] = dp[0][v] + subs[v].first;
dfs_ans(v, u);
dp[0][u] = a;
dp[1][u] = b;
dp[0][v] = c;
dp[1][v] = d;
subs[u] = e;
}
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
cin >> n;
G.resize(n);
for(int i = 0; i < n - 1; i ++){
int u, v, w; cin >> u >> v >> w;
-- u; -- v;
G[u].push_back({v, w});
G[v].push_back({u, w});
}
dfs_dp(0, 0);
dfs_ans(0, 0);
cout << ans << endl;
}
