#include <bits/stdc++.h>
// #define int long long
using namespace std;
struct mem{
int x, y, z;
};
mem a[150001];
vector<int> luu[300005];
vector<int> tr[300005];
vector<int> trz[300005];
int inf = -1e9;
int n;
struct pst{
struct Node{
int val;
int l, r;
Node(int v){
val = v;
l = -1, r= -1;
}
};
vector<Node> luu;
void clear(){
luu.clear();
}
int build(int start, int end){
if(start==end){
Node tmp(inf);
luu.push_back(tmp);
return luu.size()-1;
}else{
int mid = (start+end)/2;
Node tmp(inf);
int t = build(start, mid);
int p = build(mid+1, end);
tmp.l = t, tmp.r = p;
luu.push_back(tmp);
return luu.size()-1;
}
}
int update(int start, int end, int p, int x, int id){
if(start==end){
Node tmp(0);
tmp.val = luu[id].val;
tmp.val = max(tmp.val, x);
luu.push_back(tmp);
return luu.size()-1;
}else{
int mid = (start+end)/2;
Node tmp(0);
tmp.val = luu[id].val;
tmp.l = luu[id].l, tmp.r = luu[id].r;
if(p<=mid){
int tr = update(start, mid, p, x, luu[id].l);
tmp.l = tr;
}else{
int tr = update(mid+1, end, p, x, luu[id].r);
tmp.r = tr;
}
tmp.val = max(luu[tmp.l].val, luu[tmp.r].val);
luu.push_back(tmp);
return luu.size()-1;
}
}
int query(int start, int end, int l, int r, int id){
if(start > r or end<l)return inf;
if(l<=start and end<=r){
return luu[id].val;
}
int mid = (start+end)/2;
return max(query(start, mid, l, r, luu[id].l), query(mid+1,end, l, r, luu[id].r));
}
};
pst cay[300005];
vector<int> seg[300005];
vector<int> pf[300005], lz[300005]; //X
void merge(vector<int> &a, vector<int> &b, vector<int> &c, int node){
int i = 1, j = 1;
while(i<a.size() and j<b.size()){
if(a[i] < b[j]){
c.push_back(a[i]);
trz[node].push_back(trz[2*node][i]);
pf[node].push_back(pf[2*node][i]);
i++;
}else{
c.push_back(b[j]);
trz[node].push_back(trz[2*node+1][j]);
pf[node].push_back(pf[2*node+1][j]);
j++;
}
}
while(i<a.size()){
c.push_back(a[i]);
trz[node].push_back(trz[2*node][i]);
pf[node].push_back(pf[2*node][i]);
i++;
}
while(j<b.size()){
c.push_back(b[j]);
pf[node].push_back(pf[2*node+1][j]);
trz[node].push_back(trz[2*node+1][j]);
j++;
}
}
void merge2(vector<int> &a, vector<int> &b, vector<int> &c){
int i = 1, j = 1;
while(i<a.size() and j<b.size()){
if(a[i] < b[j]){
c.push_back(a[i]);
i++;
}else{
c.push_back(b[j]);
j++;
}
}
while(i<a.size()){
c.push_back(a[i]);
i++;
}
while(j<b.size()){
c.push_back(b[j]);
j++;
}
}
void reset(){
for (int i = 1;i<2*n;++i){
tr[i].clear();
trz[i].clear();
luu[i].clear();
pf[i].clear();
lz[i].clear();
seg[i].clear();
cay[i].clear();
}
}
void build(){
for (int i = 1;i<=n;++i){
tr[i+n-1].push_back(-1);
trz[i+n-1].push_back(-1);
luu[i+n-1].push_back(-1);
pf[i+n-1].push_back(-1);
lz[i+n-1].push_back(-1);
pf[i+n-1].push_back(a[i].x);
tr[i+n-1].push_back(a[i].y);
luu[i+n-1].push_back(a[i].z);
trz[i+n-1].push_back(a[i].z);
lz[i+n-1].push_back(a[i].z);
int m=tr[i+n-1].size()-1;
int root = cay[i+n-1].build(1, m);
seg[i+n-1].push_back(root);
for (int j = 1;j<=m;++j){
int p = lower_bound(luu[i+n-1].begin(), luu[i+n-1].end(), trz[i+n-1][j])-luu[i+n-1].begin();
int nr = cay[i+n-1].update(1, m, p, pf[i+n-1][j], seg[i+n-1].back());
seg[i+n-1].push_back(nr);
}
}
for (int i = n-1;i>=1;--i){
tr[i].push_back(-1);
trz[i].push_back(-1);
luu[i].push_back(-1);
pf[i].push_back(-1);
lz[i].push_back(-1);
merge(tr[2*i], tr[2*i+1], tr[i], i);
merge2(luu[2*i], luu[2*i+1], luu[i]);
int m=tr[i].size()-1;
int root = cay[i].build(1, m);
seg[i].push_back(root);
for (int j = 1;j<=m;++j){
int p = lower_bound(luu[i].begin(), luu[i].end(), trz[i][j])-luu[i].begin();
int nr = cay[i].update(1, m, p, pf[i][j], seg[i].back());
seg[i].push_back(nr);
}
for (int j = 1;j<=m;++j){
lz[i].push_back(trz[i][j]);
lz[i][j] = max(lz[i][j], lz[i][j-1]);
}
}
}
int q1(int l, int r, int y){
l = l+n-1, r = r+n-1;
int res = -1;
while(l<=r){
if(l&1){
int p = lower_bound(tr[l].begin(), tr[l].end(), y)-tr[l].begin()-1;
res = max (res, lz[l][p]);
l++;
}
if(!(r&1)){
int p = lower_bound(tr[r].begin(), tr[r].end(), y)-tr[r].begin()-1;
res = max (res, lz[r][p]);
r--;
}
l/=2;
r/=2;
}
return res;
}
int q2(int l, int r, int y, int z){
l = l+n-1, r = r+n-1;
int res = inf;
while(l<=r){
if(l&1){
int p = lower_bound(tr[l].begin(), tr[l].end(), y)-tr[l].begin()-1;
int m = tr[l].size()-1;
int q = lower_bound(luu[l].begin(), luu[l].end(), z)-luu[l].begin()-1;
int sol = cay[l].query(1, m, 1, q, seg[l][p]);
res = max(res, sol);
l++;
}
if(!(r&1)){
int p = lower_bound(tr[r].begin(), tr[r].end(), y)-tr[r].begin()-1;
int m = tr[r].size()-1;
int q = lower_bound(luu[r].begin(), luu[r].end(), z)-luu[r].begin()-1;
int sol = cay[r].query(1, m, 1, q, seg[r][p]);
res = max(res, sol);
r--;
}
l/=2;
r/=2;
}
return res;
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
// freopen("team_contest.inp","r",stdin);
// freopen("team_contest.out","w",stdout);
cin >> n;
for (int i = 1;i<=n;++i){
cin >> a[i].x >> a[i].y >> a[i].z;
}
sort(a+1, a+n+1, [](mem p, mem q){
return p.x < q.x;
});
for (int i = 1;i<=n;++i){
// cout << a[i].x << ' ' << a[i].y << ' ' << a[i].z << '\n';
}
int tro = 1;
// return 0;
build();
// return 0;
int res = -1;
for (int i = 2;i<=n;++i){
while(tro<=n and a[tro].x<=a[i].x){
tro++;
}
int mz = q1(1, i-1, a[i].y);
if(mz > a[i].z){
int sol = q2(tro, n, a[i].y, mz);
if(sol!=inf){
res = max(res, a[i].y + mz + sol);
}
}
}
// return 0;
// cout << res << '\n';
reset();
for (int i = 1;i<=n;++i){
swap(a[i].y, a[i].z);
}
tro = 1;
build();
// return 0;
// int res = 0;
for (int i = 2;i<=n;++i){
while(tro<=n and a[tro].x<=a[i].x){
tro++;
}
int mz = q1(1, i-1, a[i].y);
if(mz > a[i].z){
int sol = q2(tro, n, a[i].y, mz);
if(sol!=inf){
res = max(res, a[i].y + mz + sol);
// cout << res << ' ' << mz << ' ' << i << '\n';
}
}
}
cout << res;
}
