#include <bits/stdc++.h>
#ifdef __LOCAL__
#include <debug_local.h>
#endif
using namespace std;
void testCase() {
int n;
cin >> n;
vector<int> x(n), y(n), z(n);
for (int i = 0; i < n; i++) cin >> x[i] >> y[i] >> z[i];
set<pair<int, int>> s1, s2, s3;
for (int i = 0; i < n; i++) {
s1.insert({x[i], i});
s2.insert({y[i], i});
s3.insert({z[i], i});
}
int ans = -1;
auto erase = [&](int i) {
s1.erase({x[i], i});
s2.erase({y[i], i});
s3.erase({z[i], i});
return 1;
};
while (!s1.empty()) {
auto [a, i] = *s1.rbegin();
auto [b, j] = *s2.rbegin();
auto [c, k] = *s3.rbegin();
if (z[i] == c || y[i] == b) {
erase(i);
continue;
}
if (z[j] == c || x[j] == a) {
erase(j);
continue;
}
if (x[k] == a || y[k] == b) {
erase(k);
continue;
}
break;
}
if (s1.empty()) cout << ans << "\n";
else {
auto [a, i] = *s1.rbegin();
auto [b, j] = *s2.rbegin();
auto [c, k] = *s3.rbegin();
cout << a + b + c << "\n";
}
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
testCase();
}
