#include <bits/stdc++.h>
using namespace std;
void chmax(int &x, const int &y) {
x = (x > y ? x : y);
}
struct Fenwick {
vector<int> f;
int n;
Fenwick(int n_) : n(n_) {
f.resize(n);
}
void upd(int i, int x) {
while (i < n) {
chmax(f[i], x);
i |= i + 1;
}
}
int qry(int i) {
int x = 0;
while (i >= 0) {
chmax(x, f[i]);
i = (i & i + 1) - 1;
}
return x;
}
};
struct custom_hash {
static uint64_t splitmix64(uint64_t x) {
// http://xorshift.di.unimi.it/splitmix64.c
x += 0x9e3779b97f4a7c15;
x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
return x ^ (x >> 31);
}
size_t operator()(uint64_t x) const {
static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
return splitmix64(x + FIXED_RANDOM);
}
};
struct Fenwick2D {
vector<unordered_map<int, int, custom_hash>> f;
int nx, ny;
Fenwick2D(int nx_, int ny_) : nx(nx_), ny(ny_) {
f.resize(nx_);
}
void upd(int i, int J, int x) {
while (i >= 0) {
for (int j = J; j >= 0; j = (j & j + 1) - 1) {
chmax(f[i][j], x);
}
i = (i & i + 1) - 1;
}
}
int qry(int i, int J) {
int x = 0;
while (i < nx) {
for (int j = J; j < ny; j |= j + 1) {
chmax(x, f[i][j]);
}
i |= i + 1;
}
return x;
}
};
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
int n;
cin >> n;
vector<tuple<int, int, int>> a(n);
vector<int> cmpx, cmpy, cmpz;
for (auto &[x, y, z] : a) {
cin >> x >> y >> z;
cmpx.push_back(x);
cmpy.push_back(y);
cmpz.push_back(z);
}
sort(cmpx.begin(), cmpx.end());
cmpx.erase(unique(cmpx.begin(), cmpx.end()), cmpx.end());
sort(cmpy.begin(), cmpy.end());
cmpy.erase(unique(cmpy.begin(), cmpy.end()), cmpy.end());
sort(cmpz.begin(), cmpz.end());
cmpz.erase(unique(cmpz.begin(), cmpz.end()), cmpz.end());
vector<vector<pair<int, int>>> X(cmpx.size());
for (auto &[x, y, z] : a) {
X[lower_bound(cmpx.begin(), cmpx.end(), x) - cmpx.begin()].push_back({lower_bound(cmpy.begin(), cmpy.end(), y) - cmpy.begin(), lower_bound(cmpz.begin(), cmpz.end(), z) - cmpz.begin()});
}
Fenwick fy(cmpy.size()), fz(cmpz.size());
Fenwick2D fyz(cmpy.size(), cmpz.size());
int ans = -1;
for (int x = 0; x < cmpx.size(); x++) {
for (auto &[y, z] : X[x]) {
int wyz = fyz.qry(y + 1, z + 1);
if (wyz) chmax(ans, cmpx[x] + wyz);
}
for (auto &[y, z] : X[x]) {
int wz = fy.qry(y - 1), wy = fz.qry(z - 1);
if (wz > z) fyz.upd(y, wz, cmpy[y] + cmpz[wz]);
if (wy > y) fyz.upd(wy, z, cmpy[wy] + cmpz[z]);
fy.upd(y, z);
fz.upd(z, y);
}
}
cout << ans << '\n';
return 0;
}
