#include "bits/stdc++.h"
#define F first
#define S second
#define ll long long
#define pii pair<int,int>
const int mxN = 3e5 + 5;
const int mod = 1e9 + 7;
using namespace std;
bool operator<(pii a,pii b){
return make_pair(a.F,-1 * a.S) < make_pair(b.F,-1 * b.S);
}
struct node{
node *l,*r;
pii val;
node(): l(NULL), r(NULL), val({0,0}){}
};
node *root1 = new node(),*root2 = new node();
pii query(int l,int r,int s,int e,node *cur){
if(l > e || r < s) return {0,0};
if(l >= s && r <= e) return cur->val;
pii op1 = {0,0},op2 = {0,0};
int md = (l + r) / 2;
if(cur->l) op1 = query(l,md,s,e,cur->l);
if(cur->r) op2 = query(md + 1,r,s,e,cur->r);
return max(op1,op2);
}
void update(int l,int r,int ind,pii val,node *cur){
if(l == r){
cur->val = max(cur->val,val);
return;
}
int md = (l + r) / 2;
if(!cur->l) cur->l = new node();
if(!cur->r) cur->r = new node();
if(ind <= md) {
update(l,md,ind,val,cur->l);
}
else {
update(md + 1,r,ind,val,cur->r);
}
cur->val = max(cur->l->val,cur->r->val);
}
struct player{
int x,y,z;
friend bool operator<(player a, player b){
return a.x < b.x;
}
};
player a[mxN];
signed main(){
int n;
cin >>n;
int N;
for(int i = 1;i <= n;i++){
cin >>a[i].x>> a[i].y>> a[i].z;
N = max({a[i].x,a[i].y,a[i].z,N});
}
N = exp2(ceil(log2(N)));
sort(a + 1,a + n + 1);
int ans = -1;
int prev = 0;
queue<pii>buff;
for(int i = 1;i <= n;i++){
// cout<<"TES\n";
// if(a[i].x != prev){
// while(buff.size()){
//
// }
// }
pii x = query(1,N,1,a[i].y - 1,root1);
update(1,N,a[i].y,{a[i].z,a[i].y},root1);
pii y = query(1,N,a[i].y + 1,N,root2);
// cout<<"{ "<<x.F<<' '<<x.S<<" } , { "<<y.F<<' '<<y.S<<" }\n";
if(y.S){
ans = max(ans,a[i].x + y.F);
}
if(x.S) update(1,N,a[i].y,{x.F + a[i].y,a[i].y},root2);
}
cout<<ans;
}
