#include <bits/stdc++.h>
using namespace std;
using ll = long long; using pii = pair<ll,ll>;
const ll INF = 1e18;
ll ans = -1;
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 x=0;x<N;x++) {
dp0[x]=-INF;
dp1[x]=-INF;
}
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()>=1) {
dp1[x]=dp0v+vaug[vaug.size()-1]+radj[x].second;
} else {
dp1[x]=-INF;
}
}
ans = max(ans,dp0[0]);
//multiple root DP:
//dp0[x] gives value of subtree of x if you assume x is the root
//now just like dp down
ll dp0U[N]; //no blue segments with center x already created
ll dp1U[N]; //dp1U[x]: blue segment at center x, one edge up (counted), one edge down to children (not counted)
dp0U[0]=0;
dp1U[0]=-INF;
for (ll i=1;i<N;i++) {
dp0U[i]=-INF;
dp1U[i]=-INF;
}
for (ll IND=0;IND<N;IND++) {
ll x = itpls[IND];
//process all children (y) of x
//cases: y - x - y': read dp0U[x]
//y - x - p[x]: read dp1U[x]
//or no edge through x
//if y'-x edge: read dp1[y'], else read dp0[y']
//also:
//x - y - ?: write dp1U[y], else write dp0U[y]
ll sst = 0;
multiset<ll> sup;
for (pii p0: fadj[x]) {
ll y = p0.first;
ll ve = p0.second;
sst += max(dp0[y],dp1[y]);
sup.insert(dp0[y]+ve-max(dp0[y],dp1[y]));
}
//case 1: y-x-y'
if (fadj[x].size()>=2) {
for (pii p0: fadj[x]) {
ll y = p0.first;
ll ve = p0.second;
ll vdel = dp0[y]+ve-max(dp0[y],dp1[y]);
sup.erase(sup.find(vdel));
dp0U[y]=max(dp0U[y],dp0U[x]+ve+*(--sup.end())+sst-max(dp0[y],dp1[y]));
sup.insert(vdel);
}
}
//case 2: y-x-p[x]
if (dp1U[x]!=-INF) {
for (pii p0: fadj[x]) {
ll y = p0.first;
ll ve = p0.second;
dp0U[y]=max(dp0U[y],dp1U[x]+ve+sst-max(dp0[y],dp1[y]));
}
}
//case 3: child(y)-y-x
for (pii p0: fadj[x]) {
ll y = p0.first;
ll ve = p0.second;
dp1U[y]=max(dp1U[y],dp0U[x]+ve+sst-max(dp0[y],dp1[y]));
}
//case 4: no such edges
for (pii p0: fadj[x]) {
ll y = p0.first;
dp0U[y]=max(dp0U[y],dp0U[x]+sst-max(dp0[y],dp1[y]));
}
}
for (ll x=0;x<N;x++) {
ans = max(ans,dp0[x]+dp0U[x]);
}
cout << ans << "\n";
}
