#include <bits/stdc++.h>
using namespace std;
const int baza = (1<<18);
int d[2*baza][2], opt[4];
void akt(int i) {
i = (i+baza)/2;
while (i > 0)
d[i][0] = max(d[2*i][0],d[2*i+1][0]), d[i][1] = max(d[2*i][1],d[2*i+1][1]), i >>= 1;
}
int maks(int l, int r, int t) {
l += baza-1, r += baza+1; int w = 0;
while (l/2 != r/2) {
if ((l&1) == 0)
w = max(w,d[l+1][t]);
if ((r&1) == 1)
w = max(w,d[r-1][t]);
l >>= 1, r >>= 1;
}
return w;
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
int n, odp = -1; cin >> n;
map<int,int> mpy, mpz; int x,y,z;
map<int,vector<pair<int,int>>> mp;
for (int i = 0; i < n; i++)
cin >> x >> y >> z, mp[x].push_back({y,z}), mpy[y] = 0, mpz[z] = 0;
int cnt = 1;
for (auto it = mpy.begin(); it != mpy.end(); it++)
mpy[it->first] = cnt++;
cnt = 1;
for (auto it = mpz.begin(); it != mpz.end(); it++)
mpz[it->first] = cnt++;
for (auto it = mp.begin(); it != mp.end(); it++) {
for (auto [a,b] : it->second) {
if (a < opt[0] && b < opt[1])
odp = max(odp,it->first+opt[0]+opt[1]);
if (a < opt[2] && b < opt[3])
odp = max(odp,it->first+opt[2]+opt[3]);
}
for (auto [a,b] : it->second) {
int c = mpy[a], e = mpz[b], yz = maks(0,c-1,0), zy = maks(0,e-1,1);
if (yz > b && c >= opt[0])
opt[0] = a, opt[1] = yz;
if (zy > a && e >= opt[3])
opt[2] = zy, opt[3] = b;
d[c+baza][0] = max(d[c+baza][0],b), akt(c), d[e+baza][1] = max(d[e+baza][1],a), akt(e);
}
}
cout << odp << endl;
return 0;
}
