#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ull unsigned long long
#define ld long double
#define ff first
#define ss second
#define ln "\n"
#define mp make_pair
#define pb push_back
#define INF (ll)2e18
#define MOD (ll)(1e9+7)
struct Fenwick2d{
vector<map<ll, ll>> tr;
ll offs=0, n;
Fenwick2d(ll N){
n=N+20; offs=10;
tr.resize(n+1);
}
void add(ll _i, ll _j, ll x){
// cout << _i << " " << _j << " +" << x << ln;
_i+=offs; _j+=offs;
for (ll i=_i; i; i-=(-i&i)){
for (ll j=_j; j; j-=(-j&j)){
tr[i][j]=max(tr[i][j], x);
}
}
}
ll get(ll _i, ll _j){
// cout << _i << " " << _j << " get: ";
_i+=offs; _j+=offs; ll res=-1;
for (ll i=_i; i<=n; i+=(-i&i)){
for (ll j=_j; j<=n; j+=(-j&j)){
if (tr[i].count(j)) res=max(res, tr[i][j]);
}
}
// cout << res << ln;
return res;
}
};
struct Fenwick{
vector<ll> tr;
ll offs, n;
Fenwick(ll N){
n=N+20; offs=10;
tr.resize(n+1);
}
void add(ll i, ll x){
i+=offs; for (; i<=n; i+=(-i&i)) tr[i]=max(tr[i], x);
}
ll get(ll i){
i+=offs;
ll res=-1; for (; i; i-=(-i&i)) res=max(res, tr[i]);
return res;
}
};
void solve(){
ll n; cin >> n;
map<ll, vector<pair<ll, ll>>> a;
vector<ll> xs, ys, zs;
vector<array<ll, 3>> vals(n);
for (ll i=0; i<n; i++){
ll x, y, z; cin >> x >> y >> z;
vals[i] = {x, y, z}; xs.push_back(x);
ys.push_back(y); zs.push_back(z);
}
sort(xs.begin(), xs.end()); xs.erase(unique(xs.begin(), xs.end()), xs.end());
sort(ys.begin(), ys.end()); ys.erase(unique(ys.begin(), ys.end()), ys.end());
sort(zs.begin(), zs.end()); zs.erase(unique(zs.begin(), zs.end()), zs.end());
for (ll i=0; i<n; i++){
ll x = lower_bound(xs.begin(), xs.end(), vals[i][0])-xs.begin();
ll y = lower_bound(ys.begin(), ys.end(), vals[i][1])-ys.begin();
ll z = lower_bound(zs.begin(), zs.end(), vals[i][2])-zs.begin();
a[x].push_back({y, z});
}
Fenwick2d pos(n);
Fenwick posy(n), posz(n);
ll res=-1;
for (auto &[x, ar]:a){
for (auto [y, z]:ar){
ll psx = pos.get(y+1, z+1);
if (psx!=-1) res=max(res, psx+xs[x]);
}
for (auto [y, z]:ar){
ll dz = posy.get(y-1);
ll dy = posz.get(z-1);
if (dz>z){
// cout << ys[y] << "&" << zs[dz] << " at " << xs[x] << ln;
pos.add(y, dz, ys[y]+zs[dz]);
}
if (dy>y){
// cout << ys[dy] << "&" << zs[z] << " at " << xs[x] << ln;
pos.add(dy, z, ys[dy]+zs[z]);
}
posy.add(y, z); posz.add(z, y);
}
}
cout << res << ln;
}
int main(){
ios_base::sync_with_stdio(false); cin.tie(nullptr);
#ifdef LOCAL
auto start = chrono::high_resolution_clock::now();
#endif
ll t=1;
// cin >> t;
for (ll c=1; c<=t; c++) solve();
#ifdef LOCAL
auto duration = chrono::duration_cast<chrono::microseconds>(chrono::high_resolution_clock::now() - start);
cout << setprecision(0) << fixed << "time: " << (double)duration.count()/1000.0 << " milliseconds" << endl;
#endif
}
