#include <bits/stdc++.h>
#define fi first
#define se second
using namespace std;
using ll = long long;
const int N = 150005;
int n, inf = 1e9, ans = -1;
struct kid {
int x,y,z;
} p[N];
vector <int> nen;
int seg[4*N], bit[N], luu[4*N];
void update(int id, int val) {
while(id <= n) bit[id] = max(bit[id], val), id += -id&id;
}
int get(int id) {
int res = -1;
while(id > 0) res = max(res, bit[id]), id -= -id&id;
return res;
}
void up(int x, int l, int r, int id, int w) {
if(l == r) {
int vl = nen[id] + w;
if(seg[x] < vl || (seg[x] == vl && luu[x] < w))
seg[x] = vl, luu[x] = w;
return;
}
int m = (l + r)/2;
if(id <= m) up(2*x,l,m,id,w);
else up(2*x+1,m+1,r,id,w);
seg[x] = seg[2*x];
luu[x] = luu[2*x];
if(seg[x] < seg[2*x+1] || (seg[x] == seg[2*x+1] && luu[x] < luu[2*x+1]))
seg[x] = seg[2*x+1], luu[x] = luu[2*x+1];
}
pair <int,int> MAX(int x, int l, int r, int i, int j) {
if(l > j || r < i) return make_pair(-1,-1);
if(l >= i && r <= j) return make_pair(seg[x], luu[x]);
int m = (l + r)/2;
pair <int,int> res = MAX(2*x,l,m,i,j);
pair <int,int> RES = MAX(2*x+1,m+1,r,i,j);
if(res.fi > RES.fi || (res.fi == RES.fi && res.se > RES.se)) return res;
return RES;
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n;
fill(seg, seg+4*n+1, -1);
for(int i=1;i<=n;++i) cin >> p[i].x >> p[i].y >> p[i].z, nen.push_back(p[i].y);
sort(p+1,p+n+1, [&](const kid & p1, const kid & p2) {
if(p1.x != p2.x) return p1.x < p2.x;
else if(p1.y != p2.y) return p1.y < p2.y;
return p1.z < p2.z;
});
//cout << '\n';
//for(int i=1;i<=n;++i) cout << p[i].x << ' ' << p[i].y << ' ' << p[i].z << '\n'; cout << '\n';
nen.push_back(0);
sort(nen.begin(), nen.end());
nen.erase(unique(nen.begin(), nen.end()), nen.end());
for(int i=1;i<=n;++i) {
p[i].y = lower_bound(nen.begin(), nen.end(), p[i].y) - nen.begin();
}
set <int> ms;
int j = 1;
for(int i=1;i<=n;++i) {
while(p[i].x == p[j].x) ++j;
if(!ms.empty()) {
for(int id=i;id<j;++id) {
int Y = p[id].y, Z = p[id].z;
auto it = ms.upper_bound(Y);
if(it == ms.end()) continue;
int yi = *it;
pair <int,int> kq = {-1,-1};
if(yi <= n) kq = MAX(1,1,n,yi,n);
if(kq.se > Z) ans = max(ans, p[i].x + kq.fi);
//cout << id << ' ' << yi << ' ' << kq.fi << ' ' << kq.se << '\n';
}
}
for(int id=i;id<j;++id) {
int Y = p[id].y, Z = p[id].z;
update(Y, Z);
int val = get(Y - 1);
if(val > Z) up(1,1,n,Y,val);
ms.insert(Y);
}
// cout << ans << '\n';
}
cout << ans;
return 0;
}
