#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];
int comp[N], nen[N], ind, bit[N], Minz[N], seg[4*N];
////// BIT
void update(int id, int vl) {
while(id <= ind) bit[id] = max(bit[id], vl), id += -id&id;
}
int getmax(int id) {
int res = -1;
while(id > 0) res = max(res, bit[id]), id -= -id&id;
return res;
}
////////// ST
void up(int x, int l, int r, int id, int w) {
if(l == r) {
seg[x] = max(seg[x], w + nen[id]);
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] = max(seg[2*x+1], seg[2*x]);
}
int MAX(int x, int l, int r, int i, int j) {
if(l > j || r < i) return -1;
if(l >= i && r <= j) return seg[x];
int m = (l+r)/2;
return max(MAX(2*x,l,m,i,j), MAX(2*x+1,m+1,r,i,j));
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
fill(bit, bit+N, -1);
fill(seg, seg+4*N, -1);
cin >> n;
for(int i=1;i<=n;++i) cin >> p[i].x >> p[i].y >> p[i].z, comp[i] = p[i].y;
sort(p+1,p+n+1, [&](const kid & p1, const kid & p2) {
return p1.x < p2.x;
return p1.y < p2.y;
return p1.z < p2.z;
});
sort(comp+1,comp+n+1);
for(int i=1;i<=n;++i) if(comp[i] != nen[ind]) nen[++ind] = comp[i];
for(int i=1;i<=n;++i) p[i].y = lower_bound(nen+1, nen+ind+1, p[i].y) - nen;
//cout<<'\n';for(int i=1;i<=n;++i) cout<<p[i].x<<' '<<p[i].y<<' '<<p[i].z<<'\n';
//cout<<'\n';
int j = 1;
for(int i=1;i<=n;i = j) {
while(p[i].x == p[j].x) ++j;
if(i != 1) {
int idd = i;
for(int id=i;id<j;id = idd) {
while(p[id].y == p[idd].y && idd < j) ++idd;
int Y = p[id].y, Z = p[id].z, ID = ind+1;
int l = 1, r = ind;
while(l <= r) {
int mid = (l+r)/2;
if(getmax(mid) > Z) ID = mid, r = mid - 1;
else l = mid + 1;
}
ID = max(ID+1, Y+1);
if(ID <= ind) ans = max(ans, p[i].x + MAX(1,1,ind,ID,ind));
}
}
for(int id=i;id<j;++id) {
int Y = p[id].y, Z = p[id].z;
update(Y, Z);
int val = getmax(Y - 1);
if(val > Z) up(1, 1, ind, Y, val);
}
}
cout << ans;
return 0;
}
