#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5e4 + 5, INF = 1e9 + 7;
int n;
struct ele{
int x, y, z;
} a[N];
template <typename T>
struct Fenwick {
int n;
std::vector<T> a;
Fenwick(int n_ = 0) {
init(n_);
}
void init(int n_) {
n = n_;
a.assign(n + 5, T{});
}
void upd(int x, const T &v) {
for (int i = x; i <= n; i += i & -i) {
a[i] = max(a[i], v);
}
}
T get(int x) {
T ans{};
for (int i = x; i > 0; i -= i & -i) {
ans = max(ans, a[i]);
}
return ans;
}
T get(int l, int r) {
return get(r) - get(l - 1);
}
int kth(const T &k) {
int x = 0;
T cur{};
for (int i = 20; i >= 0; i--) {
if (x + (1 << i) <= n && cur + a[x + (1 << i)] < k) {
x += (1 << i);
cur = cur + a[x];
}
}
return x + 1;
}
};
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> n;
vector<int> Y, Z;
Z.push_back(0), Y.push_back(0);
for(int i = 0; i < n; i++){
cin >> a[i].x >> a[i].y >> a[i].z;
Y.push_back(a[i].y);
Z.push_back(a[i].z);
}
sort(Y.begin(), Y.end()), Y.resize(unique(Y.begin(), Y.end()) - Y.begin());
sort(Z.begin(), Z.end()), Z.resize(unique(Z.begin(), Z.end()) - Z.begin());
sort(a, a + n, [&](ele x, ele y){ return x.x < y.x; });
Fenwick<int> fy(n + 1), fz(n + 1);
fill(fy.a.begin(), fy.a.end(), -INF);
fill(fz.a.begin(), fz.a.end(), -INF);
int ans = -INF, j = 0;
int z = -INF, y = -INF;
for(int i = 0; i < n; i++){
a[i].y = lower_bound(Y.begin(), Y.end(), a[i].y) - Y.begin();
a[i].z = lower_bound(Z.begin(), Z.end(), a[i].z) - Z.begin();
while(a[j].x < a[i].x){
int zz = fy.get(a[j].y - 1), yy = fz.get(a[j].z - 1);
if(zz > Z[a[j].z] && zz + Y[a[j].y] >= z + y) z = zz, y = Y[a[j].y];
if(yy > Y[a[j].y] && yy + Z[a[j].z] >= z + y) z = Z[a[j].z], y = yy;
fy.upd(a[j].y, Z[a[j].z]);
fz.upd(a[j].z, Y[a[j].y]);
j++;
}
if(z > Z[a[i].z] && y > Y[a[i].y]) ans = max(ans, a[i].x + y + z);
}
cout << (ans > 0 ? ans : -1) << '\n';
}
