#include <bits/stdc++.h>
#include <ostream>
#define int long long
using namespace std;
struct Contestant {
int x, y, z;
};
signed main(void) {
ios_base::sync_with_stdio(false);
cin.tie(0);
int N;
cin >> N;
vector<Contestant> contestants(N);
for (auto &[x, y, z] : contestants)
cin >> x >> y >> z;
vector<int> ordX(N), ordY(N), ordZ(N);
for (int i = 0; i < N; ++i)
ordX[i] = ordY[i] = ordZ[i] = i;
sort(ordX.begin(), ordX.end(), [&](int i, int j) {
return pair(contestants[i].x, i) < pair(contestants[j].x, j);
});
sort(ordY.begin(), ordY.end(), [&](int i, int j) {
return pair(contestants[i].y, i) < pair(contestants[j].y, j);
});
sort(ordZ.begin(), ordZ.end(), [&](int i, int j) {
return pair(contestants[i].z, i) < pair(contestants[j].z, j);
});
int posX = N - 1, posY = N - 1, posZ = N - 1;
vector<bool> erased(N);
while (posX >= 0 and posY >= 0 and posZ >= 0) {
int ix = ordX[posX], iy = ordY[posY], iz = ordZ[posZ];
int X = contestants[ordX[posX]].x, Y = contestants[ordY[posY]].y,
Z = contestants[ordZ[posZ]].z;
if (Y == contestants[ix].y or Z == contestants[ix].z)
erased[ix] = true;
else if (X == contestants[iy].x or Z == contestants[iy].z)
erased[iy] = true;
else if (X == contestants[iz].x or Y == contestants[iz].y)
erased[iz] = true;
else {
cout << X + Y + Z << endl;
return 0;
}
while (posX >= 0 and erased[ordX[posX]])
--posX;
while (posY >= 0 and erased[ordY[posY]])
--posY;
while (posZ >= 0 and erased[ordZ[posZ]])
--posZ;
}
cout << -1 << endl;
}
