#include <bits/stdc++.h>
#define task "Team Contest"
#define ll long long
#define fi first
#define se second
#define ld long double
#define pii pair<int, int>
#define all(x) (x).begin(), (x).end()
using namespace std;
struct Node
{
int x, y, z;
};
const int N = 15e4 + 5;
Node a[N];
pii mx1[N], mx2[N];
int n;
vector<int> node[N], bit[N];
vector<int> ys, zs;
void fakeUpd(int i, int j)
{
for (int x = i; x > 0; x -= x&-x) node[x].push_back(j);
}
void fakeGet(int i, int j)
{
for (int x = i; x <= ys.size(); x += x&-x) node[x].push_back(j);
}
void upd(int i, int j, int v)
{
for (int x = i; x > 0; x -= x&-x)
for (int y = lower_bound(all(node[x]), j)-node[x].begin()+1; y > 0; y -= y&-y) bit[x][y-1] = max(bit[x][y-1], v);
}
int get(int i, int j)
{
int res = 0;
for (int x = i; x <= ys.size(); x += x&-x)
for (int y = lower_bound(all(node[x]), j)-node[x].begin()+1; y <= node[x].size(); y += y&-y) res = max(res, bit[x][y-1]);
return res;
}
struct maxBIT
{
vector<int> bit;
int n;
void init(int n_)
{
n = n_;
bit.assign(n+1, 0);
}
void upd(int i, int v)
{
for (; i <= n; i += i&-i) bit[i] = max(bit[i], v);
}
int get(int i)
{
int res = 0;
for (; i; i -= i&-i) res = max(res, bit[i]);
return res;
}
} mbit;
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
if (fopen(task".inp", "r"))
{
freopen(task".inp", "r", stdin);
freopen(task".out", "w", stdout);
}
cin >> n;
for (int i = 1; i <= n; i++)
{
cin >> a[i].x >> a[i].y >> a[i].z;
ys.push_back(a[i].y);
zs.push_back(a[i].z);
}
sort(all(ys));
ys.erase(unique(all(ys)), ys.end());
sort(all(zs));
zs.erase(unique(all(zs)), zs.end());
sort(a+1, a+n+1, [&](const Node &x, const Node &y){ return x.x < y.x; });
for (int i = 1; i <= n; i++)
{
auto &[x, y, z] = a[i];
y = lower_bound(all(ys), y) - ys.begin() + 1;
z = lower_bound(all(zs), z) - zs.begin() + 1;
}
mbit.init(ys.size());
for (int i = 1; i <= n; i++)
{
auto &[x, y, z] = a[i];
mx1[i] = {y, mbit.get(y-1)};
mbit.upd(y, z);
}
mbit.init(zs.size());
for (int i = 1; i <= n; i++)
{
auto &[x, y, z] = a[i];
mx2[i] = {mbit.get(z-1), z};
mbit.upd(z, y);
}
for (int i = 1; i <= n; i++)
{
int y = mx1[i].fi, z = mx1[i].se;
if (y && z) fakeUpd(y, z);
y = mx2[i].fi, z = mx2[i].se;
if (y && z) fakeUpd(y, z);
fakeGet(a[i].y+1, a[i].z+1);
}
for (int i = 1; i <= ys.size(); i++)
{
sort(all(node[i]));
node[i].erase(unique(all(node[i])), node[i].end());
bit[i].resize(node[i].size());
}
int j = 1, res = 0;
for (int i = 1; i <= n; i++)
{
auto &[x, y, z] = a[i];
while (j <= n && a[j].x < x)
{
int y = mx1[j].fi, z = mx1[j].se;
if (y && z) upd(y, z, ys[y-1]+zs[z-1]);
y = mx2[j].fi, z = mx2[j].se;
if (y && z) upd(y, z, ys[y-1]+zs[z-1]);
j++;
}
int tmp = get(y+1, z+1);
if (tmp) res = max(res, tmp+x);
}
cout << (res == 0 ? -1 : res);
return 0;
}
