#include<bits/stdc++.h>
using namespace std;
#define nd second
#define st first
#define pb push_back
typedef long long ll;
typedef long double ld;
const int N = 1<<18;
pair<int, pair<int, int>> tab[N];
pair<int, int> sk[N];
int drzy[2 * N], drzz[2 * N];
void AddY(int v, int il)
{
v += N;
while(v > 0)
{drzy[v] = max(drzy[v], il); v /= 2;}
}
void AddZ(int v, int il)
{
v += N;
while(v > 0)
{drzz[v] = max(drzz[v], il); v /= 2;}
}
int MaxY(int a, int b)
{
a += N; b += N;
int w = max(drzy[a], drzy[b]);
while(a / 2 != b / 2)
{
if(a % 2 == 0) w = max(w, drzy[a + 1]);
if(b % 2 == 1) w = max(w, drzy[b - 1]);
a /= 2; b /= 2;
}
return w;
}
int MaxZ(int a, int b)
{
a += N; b += N;
int w = max(drzy[a], drzz[b]);
while(a / 2 != b / 2)
{
if(a % 2 == 0) w = max(w, drzz[a + 1]);
if(b % 2 == 1) w = max(w, drzz[b - 1]);
a /= 2; b /= 2;
}
return w;
}
void Skaluj(int n)
{
int l = 0;
vector<pair<int, int>> v;
for(int i = 1; i <= n; ++i)
v.pb(make_pair(tab[i].nd.st, i));
sort(v.begin(), v.end());
for(int i = 0; i < n; ++i)
{
if(i == 0 || v[i].st != v[i - 1].st) ++l;
sk[v[i].nd].st = l;
}
v.clear(); l = 0;
for(int i = 1; i <= n; ++i)
v.pb(make_pair(tab[i].nd.nd, i));
sort(v.begin(), v.end());
for(int i = 0; i < n; ++i)
{
if(i == 0 || v[i].st != v[i - 1].st) ++l;
sk[v[i].nd].nd = l;
}
}
void Solve()
{
int n, p = 1;
pair<int, int> am = make_pair(0, 0), ca;
pair<int, pair<int, pair<int, int>>> ans = make_pair(-1, make_pair(0, make_pair(0, 0)));
cin >> n;
for(int i = 1; i <= n; ++i)
cin >> tab[i].st >> tab[i].nd.st >> tab[i].nd.nd;
sort(tab + 1, tab + 1 + n);
Skaluj(n);
for(int i = 1; i <= n; ++i)
{
//cout << "d: " << tab[i].st << " " << tab[i].nd.st << " " << tab[i].nd.nd << "\n";
//cout << sk[i].st << " " << sk[i].nd << " : " << am.st << " " << am.nd << "\n";
if(am.st != 0)
if(am.st > tab[i].nd.st && am.nd > tab[i].nd.nd)
ans = max(ans, make_pair(tab[i].st + am.st + am.nd, make_pair(tab[i].st, am)));
if(tab[i].st != tab[i + 1].st)
{
for(int j = p; j <= i; ++j)
{
ca = make_pair(tab[j].nd.st, MaxZ(0, sk[j].st - 1));
if(ca.nd > tab[j].nd.nd && ca.st != 0 && ca.st >= am.st) am = max(am, ca);
ca = make_pair(MaxY(0, sk[j].nd - 1), tab[j].nd.nd);
if(ca.st > tab[j].nd.st && ca.nd != 0 && ca.st >= am.st) am = max(am, ca);
AddY(sk[j].nd, tab[j].nd.st);
AddZ(sk[j].st, tab[j].nd.nd);
}
p = i + 1;
}
}
cout << ans.st << "\n";
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
Solve();
return 0;
}
