#include <bits/stdc++.h>
using namespace std;
using ll = long long; using pii = pair<ll,ll>;
const ll INF = 1e18;
int main() {
ios_base::sync_with_stdio(false); cin.tie(0);
ll N; cin >> N;
vector<pii> adj[N];
for (ll i=0;i<(N-1);i++) {
ll a,b,c; cin >> a >> b >> c;
a--; b--;
adj[a].push_back({b,c});
adj[b].push_back({a,c});
}
vector<pii> fadj[N];
pii radj[N];
queue<ll> q0;
q0.push(0);
radj[0]={-1,INF};
vector<ll> itpls;
while (!q0.empty()) {
ll x = q0.front(); q0.pop();
itpls.push_back(x);
for (pii p0: adj[x]) {
if (p0.first!=radj[x].first) {
fadj[x].push_back(p0);
radj[p0.first]={x,p0.second};
q0.push(p0.first);
}
}
}
//dp: sum of blue
ll dp0[N]; //no blue center up
ll dp1[N]; //blue going up with center at this point
for (ll IND=(N-1);IND>=0;IND--) {
ll x = itpls[IND];
//cout << x << "\n";
if (fadj[x].size()==0) {
dp1[x]=-INF;
dp0[x]=0;
continue;
}
ll dp0v = 0;
vector<ll> vaug;
for (pii p0: fadj[x]) {
dp0v += max(dp1[p0.first],dp0[p0.first]);
vaug.push_back((dp0[p0.first]+p0.second)-max(dp1[p0.first],dp0[p0.first]));
}
sort(vaug.begin(),vaug.end());
dp0[x]=dp0v;
if (vaug.size()>=2) {
dp0[x]=max(dp0v,dp0v+vaug[vaug.size()-1]+vaug[vaug.size()-2]);
}
if (vaug.size()>=1) {
dp1[x]=dp0v+vaug[vaug.size()-1]+radj[x].second;
} else {
dp1[x]=-INF;
}
}
cout << dp0[0] <<"\n";
}
