#include<bits/stdc++.h>
using namespace std;
struct person {
int x, y, z;
};
const int N = 150000;
int w[300 + 10][300 + 10];
void add(int A, int B) {
w[A][B] = max(w[A][B], A + B);
}
void build() {
for(int i = 300; i >= 0; i--) {
for(int j = 300; j >= 0; j--) {
w[i][j] = max({w[i][j + 1], w[i + 1][j], w[i][j]});
}
}
}
vector<pair<int, int>> pnts[N + 10];
int main() {
ios::sync_with_stdio(0);
cin.tie(0), cout.tie(0);
int n;
cin >> n;
vector<person> a(n);
for(int i = 0; i < n; i++) {
cin >> a[i].x >> a[i].y >> a[i].z;
}
if(n <= 4000) {
sort(a.begin(), a.end(), [](person l, person r) {return l.z < r.z;});
int ans = 0;
for(int i = 0; i < n; i++) {
// cout << a[i].x << ' ' << a[i].y << ' ' << a[i].z << '\n';
int Y = 0, l = i + 1;
for(int j = i + 1; j < n; j++) {
if(a[j].x >= a[i].x || a[j].z == a[i].z) continue;
while (a[l].z < a[j].z) {
if(a[l].x < a[i].x) Y = max(Y, a[l].y);
l++;
}
if(Y > max(a[i].y, a[j].y)) {
ans = max(ans, a[i].x + Y + a[j].z);
}
}
int X = 0, r = i + 1;
for(int j = i + 1; j < n; j++) {
if(a[j].y >= a[i].y || a[j].z == a[i].z) continue;
while (a[r].z < a[j].z) {
if(a[r].y < a[i].y) X = max(X, a[r].x);
r++;
}
if(X > max(a[i].x, a[j].x)) {
ans = max(ans, a[i].y + X + a[j].z);
}
}
}
if(ans == 0) ans = -1;
cout << ans;
return 0;
}
sort(a.begin(), a.end(), [](person l, person r) {return l.x < r.x;});
int mxZ[300 + 10] = {}, mxY[300 + 10] = {};
for(int i = 0; i < n; i++) {
mxY[a[i].z] = max(mxY[a[i].z], a[i].y);
mxZ[a[i].y] = max(mxZ[a[i].y], a[i].z);
for(int j = a[i].z + 1; j <= 300; j++)
mxY[j] = max(mxY[j], mxY[j - 1]);
for(int j = a[i].y + 1; j <= 300; j++)
mxZ[j] = max(mxZ[j], mxZ[j - 1]);
if(mxZ[a[i].y - 1] > a[i].z)
pnts[i].push_back({a[i].y, mxZ[a[i].y - 1]});
if(mxY[a[i].z - 1] > a[i].y)
pnts[i].push_back({mxY[a[i].z - 1], a[i].z});
}
int res = 0;
int l = 0;
for(int i = 0; i < n; i++) {
while(a[l].x < a[i].x) {
for(auto [A, B] : pnts[l]) {
add(A, B);
}
l++;
}
if(i && a[i].x != a[i - 1].x) build();
if(w[a[i].y + 1][a[i].z + 1])
res = max(a[i].x + w[a[i].y + 1][a[i].z + 1], res);
}
if(res == 0) cout << -1;
else cout << res;
}
