#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
#define ALL(v) (v).begin(), (v).end()
#define MASK(i) (1LL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
// mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng(1);
ll rngesus(ll l, ll r){return ((ull) rng()) % (r - l + 1) + l;}
ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}
ll LASTBIT(ll mask){return mask & (-mask);}
ll pop_cnt(ll mask){return __builtin_popcountll(mask);}
ll ctz(ll mask){return __builtin_ctzll(mask);}
ll clz(ll mask){return __builtin_clzll(mask);}
ll logOf(ll mask){return 63 - clz(mask);}
template <class T1, class T2>
bool minimize(T1 &a, T2 b){
if (a > b){a = b; return true;}
return false;
}
template <class T1, class T2>
bool maximize(T1 &a, T2 b){
if (a < b){a = b; return true;}
return false;
}
template <class T>
void printArr(T& a, string separator = " ", string finish = "\n", ostream& out = cout){
for(auto i: a) out << i << separator;
out << finish;
}
template <class T>
void remove_dup(vector<T> &a){
sort(ALL(a));
a.resize(unique(ALL(a)) - a.begin());
}
const int N = 2e5 + 69;
const ll INF = 1e18 + 69;
int n;
vector<pair<int, int>> graph[N];
ll dp[N][2];
ll ans = 0;
void dfs(int u, int p){
for(pair<int, int> v: graph[u]) if (v.first != p){
dfs(v.first, u);
}
ll cu = 0;
ll ma = -INF;
for(pair<int, int> v: graph[u]) if (v.first != p){
dp[u][0] += max(dp[v.first][1] + v.second, dp[v.first][0]);
cu += max(dp[v.first][1] + v.second, dp[v.first][0]);
maximize(ma, (v.second + dp[v.first][0]) - max(dp[v.first][1] + v.second, dp[v.first][0]));
}
if (ma > -INF){
cu += ma;
maximize(dp[u][1], cu);
}
}
void go(int u, int p){
maximize(ans, dp[u][0]);
ll cu = 0;
ll ma = -INF, secondMa = -INF;
for(pair<int, int> v: graph[u]){
cu += max(dp[v.first][1] + v.second, dp[v.first][0]);
ll val = (v.second + dp[v.first][0]) - max(dp[v.first][1] + v.second, dp[v.first][0]);
if (ma < val){
secondMa = ma;
ma = val;
}
else maximize(secondMa, val);
}
maximize(ans, cu + ma + secondMa);
for(pair<int, int> v: graph[u]) if (v.first != p && graph[v.first].size() > 1){
ll x1 = dp[u][0], x2 = dp[u][1];
ll y1 = dp[v.first][0], y2 = dp[v.first][1];
dp[u][0] -= max(dp[v.first][1] + v.second, dp[v.first][0]);
dp[u][1] -= max(dp[v.first][1] + v.second, dp[v.first][0]);
ll val = (v.second + dp[v.first][0]) - max(dp[v.first][1] + v.second, dp[v.first][0]);
if (val == ma) dp[u][1] += secondMa - ma;
dp[v.first][0] += max(dp[u][1] + v.second, dp[u][0]);
dp[v.first][1] = 0;
ll ma = -INF;
for(pair<int, int> w: graph[v.first]) {
dp[v.first][1] += max(dp[w.first][1] + w.second, dp[w.first][0]);
maximize(ma, (w.second + dp[w.first][0]) - max(dp[w.first][1] + w.second, dp[w.first][0]));
}
dp[v.first][1] += ma;
go(v.first, u);
dp[u][0] = x1, dp[u][1] = x2;
dp[v.first][0] = y1, dp[v.first][1] = y2;
}
}
int main(void){
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n;
for(int i = 1; i<n; ++i){
int u, v, w; cin >> u >> v >> w;
graph[u].push_back({v, w});
graph[v].push_back({u, w});
}
if (n <= 2){cout << 0 << "\n"; return 0;}
for(int i = 1; i<=n; ++i) sort(ALL(graph[i]));
int root = -1;
for(int i = 1; i<=n; ++i) if (graph[i].size() > 1) root = i;
for(int i = 1; i<=n; ++i) {
dp[i][0] = 0;
dp[i][1] = -INF;
}
dfs(root, root);
go(root,root);
cout << ans << "\n";
return 0;
}
