#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#ifdef _WIN32
#define getchar_unlocked _getchar_nolock
#endif
#define int long long
#define mp make_pair
#define mt make_tuple
#define pb push_back
#define ppb pop_back
#define eb emplace_back
#define g0(a) get<0>(a)
#define g1(a) get<1>(a)
#define g2(a) get<2>(a)
#define g3(a) get<3>(a)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
using db = double;
using ll = long long;
using ld = long double;
using ii = pair<int, int>;
using iii = tuple<int, int, int>;
using iiii = tuple<int, int, int, int>;
template<class key, class value = null_type, class cmp = less<key> >
using ordered_set = tree<key, value, cmp, rb_tree_tag, tree_order_statistics_node_update>;
int N, ans, X[150005], Y[150005], Z[150005], S[150005], dX[150005], dY[150005], dZ[150005], mx[150005], _X[150005], _Y[150005], _Z[150005];
ii ft[150005];
iii T[150005];
vector<int> buffer, vX, vY, vZ;
ordered_set<iii> active_points;
int ls(int x) { return x & -x; }
int ft_qry(int p) {
ii ret = mp(0, 0);
for (; p; p -= ls(p)) ret = max(ret, ft[p]);
return ret.second;
}
void ft_upd(int p, int v) {
for (; p <= vY.size(); p += ls(p)) ft[p] = max(ft[p], mp(Z[v], v));
}
struct node {
node *left, *right;
int S, E, val;
node(int _s, int _e) : S(_s), E(_e), val(-1e9) {
if (S == E) return;
int M = (S + E) >> 1;
left = new node(S, M);
right = new node(M + 1, E);
}
void upd(int p, int v) {
if (S == E) {
val = v;
return;
}
int M = (S + E) >> 1;
if (p <= M) left->upd(p, v);
else right->upd(p, v);
val = max(left->val, right->val);
}
int qry(int l, int r) {
if (l > E || r < S) return -1e9;
if (l <= S && E <= r) return val;
return max(left->qry(l, r), right->qry(l, r));
}
} *root;
void remove_point(int x) {
root->upd(dY[x], -1e9);
}
void add_point(int x) {
if (mx[dY[x]] >= dZ[S[x]]) return;
mx[dY[x]] = dZ[S[x]];
vector<ordered_set<iii>::iterator> to_del;
// add point (dY[x], dZ[S[x]]) with value Y[x] + Z[S[x]]
auto it = active_points.upper_bound(mt(dY[x], (int)1e9, (int)1e9));
if (it != active_points.end() && g1(*it) >= dZ[S[x]]) return;
while (it != active_points.begin()) {
--it;
if (g1(*it) <= dZ[S[x]]) {
remove_point(g2(*it));
to_del.pb(it);
} else break;
}
for (auto i : to_del) active_points.erase(i);
root->upd(dY[x], Y[x] + Z[S[x]]);
active_points.insert(mt(dY[x], dZ[S[x]], x));
}
void solve() {
memset(X, 0, sizeof X);
memset(Y, 0, sizeof Y);
memset(Z, 0, sizeof Z);
memset(S, 0, sizeof S);
memset(dX, 0, sizeof dX);
memset(dY, 0, sizeof dY);
memset(dZ, 0, sizeof dZ);
memset(mx, 0, sizeof mx);
for (int i = 0; i < 150005; i++) {
ft[i] = mp(0, 0);
T[i] = mt(0, 0, 0);
}
buffer.clear();
vX.clear();
vY.clear();
vZ.clear();
active_points.clear();
for (int i = 1; i <= N; i++) {
X[i] = _X[i];
Y[i] = _Y[i];
Z[i] = _Z[i];
T[i] = mt(X[i], Y[i], Z[i]);
vX.pb(X[i]);
vY.pb(Y[i]);
vZ.pb(Z[i]);
}
sort(vX.begin(), vX.end());
vX.erase(unique(vX.begin(), vX.end()), vX.end());
sort(vY.begin(), vY.end());
vY.erase(unique(vY.begin(), vY.end()), vY.end());
sort(vZ.begin(), vZ.end());
vZ.erase(unique(vZ.begin(), vZ.end()), vZ.end());
sort(T + 1, T + 1 + N);
for (int i = 1; i <= N; i++) {
tie(X[i], Y[i], Z[i]) = T[i];
dX[i] = lower_bound(vX.begin(), vX.end(), X[i]) - vX.begin() + 1;
dY[i] = lower_bound(vY.begin(), vY.end(), Y[i]) - vY.begin() + 1;
dZ[i] = lower_bound(vZ.begin(), vZ.end(), Z[i]) - vZ.begin() + 1;
}
root = new node(1, N);
for (int i = 1; i <= N; i++) {
if (X[i] > X[i - 1]) {
for (int j : buffer) add_point(j);
buffer.clear();
}
int lo = 0, hi = (int)active_points.size() - 1, lb = -1;
while (lo <= hi) {
int mid = (lo + hi) >> 1;
if (g0(*active_points.find_by_order(mid)) > dY[i]) lb = mid, hi = mid - 1;
else lo = mid + 1;
}
lo = 0, hi = (int)active_points.size() - 1;
int rb = -1;
while (lo <= hi) {
int mid = (lo + hi) >> 1;
if (g1(*active_points.find_by_order(mid)) > dZ[i]) rb = mid, lo = mid + 1;
else hi = mid - 1;
}
if (lb != -1 && rb != -1)
ans = max(ans, X[i] + root->qry(g0(*active_points.find_by_order(lb)), g0(*active_points.find_by_order(rb))));
S[i] = ft_qry(dY[i] - 1);
ft_upd(dY[i], i);
if (Z[S[i]] > Z[i]) buffer.pb(i);
}
}
main() {
ios::sync_with_stdio(0);
cin.tie(0);
cin >> N;
for (int i = 1; i <= N; i++) cin >> _X[i] >> _Y[i] >> _Z[i];
solve();
for (int i = 1; i <= N; i++) swap(_Y[i], _Z[i]);
solve();
cout << (ans == 0 ? -1 : ans) << '\n';
}
