#include <bits/stdc++.h>
using namespace std;
#define TRACE(x) cerr << #x << " :: " << x << endl
#define _ << " " <<
#define SZ(x) (int)(x).size()
#define ALL(x) (x).begin(),(x).end()
#define FOR(i,a,b) for(int i=(a);i<=(b);++i)
#define RFOR(i,a,b) for (int i=(a);i>=(b);--i)
using ii=pair<int,int>;
using ll=long long;
const int MX_N = 2e5+5;
const int INF = 2e9+10;
int N;
vector<ii> al[MX_N];
ll f[MX_N][3], g[MX_N][2], ans = 0;
void DFS(int u, int p) {
ll best[] = {-INF,-INF};
for (ii v : al[u]) if (v.first != p) {
DFS(v.first,u);
ll val = max(f[v.first][0], f[v.first][1]+v.second);
f[u][0] += val;
ll x = f[v.first][0]+v.second - val;
FOR(i,0,1) if (x > best[i]) swap(x,best[i]);
}
if (best[0] == -INF) f[u][1] = -INF;
else f[u][1] = f[u][0] + best[0];
if (f[u][1] == -INF || best[1] == -INF) f[u][2] = -INF;
else f[u][2] = f[u][1] + best[1];
ans = max(ans, f[u][0]);
}
void DFS2(int u, int p) {
ll sum = 0;
ll best[] = {-INF,-INF};
ll bestV[] = {-1,-1};
for (ii v : al[u]) if (v.first != p) {
ll val = max(f[v.first][0], f[v.first][1]+v.second);
sum += val;
ll x = f[v.first][0]+v.second - val;
ll y = v.first;
FOR(i,0,1) if (x > best[i]) swap(x,best[i]), swap(y,bestV[i]);
}
for (ii v : al[u]) if (v.first != p) {
ll val = max(f[v.first][0], f[v.first][1]+v.second);
g[v.first][0] = max({
g[u][0] + (sum-val),
v.second + g[u][1] + (sum-val),
v.second + g[u][0] + (sum-val) + (bestV[0] == v.first ? best[1] : best[0])
});
g[v.first][1] = v.second + g[u][0] + (sum-val),
DFS2(v.first,u);
}
ans = max(ans, f[u][0] + g[u][0]);
if (f[u][1] != -INF) ans = max(ans, f[u][1] + g[u][1]);
if (f[u][2] != -INF) ans = max(ans, f[u][2] + g[u][0]);
//TRACE(u _ g[u][0] _ g[u][1]);
//TRACE(u _ f[u][0] _ f[u][1] _ f[u][2] _ g[u][0] _ g[u][1]);
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
cin >> N;
FOR(i,1,N-1){
int A, B, C; cin >> A >> B >> C;
al[A].emplace_back(B,C);
al[B].emplace_back(A,C);
}
DFS(1,0);
g[1][1] = -INF;
DFS2(1,0);
cout << ans;
}
