#include <bits/stdc++.h>
using namespace std;
using ll = int;
#define MAXN (1000005)
struct node{
ll s,e,m;
pair<ll,ll> v;
node *l, *r;
node(ll _s,ll _e){
s = _s;
e = _e;
m = (s + e) / 2;
v = {-1e9,s};
if(s != e){
l = new node(s,m);
r = new node(m + 1,e);
}
}
void update(ll x,ll nval){
if(s == e){
v.first = max(v.first,nval);
}else{
if(x > m) r -> update(x,nval);
else l -> update(x,nval);
v = max(l->v,r->v);
}
}
pair<ll,ll> rmq(ll x,ll y){
if(s == x && e == y){
return v;
}else{
if(x > m) return r->rmq(x,y);
else if(y <= m) return l->rmq(x,y);
else return max(l->rmq(x,m),r->rmq(m + 1,y));
}
}
} *rootBindtest, *rootCindtest, *rootBind, *rootCind;
int main(){
ios_base::sync_with_stdio(false);cin.tie(0);
ll N;
cin>>N;
rootBindtest = new node(0,3*N + 5);
rootCindtest = new node(0,3*N + 5);
rootBind = new node(0,3*N + 5);
rootCind = new node(0,3*N + 5);
pair<ll,pair<ll,ll> > arr[N]; //X, Y, Z
vector<ll> d;
for(ll i = 0;i < N;i++){
cin>>arr[i].first>>arr[i].second.first>>arr[i].second.second;
d.push_back(arr[i].first);
d.push_back(arr[i].second.first);
d.push_back(arr[i].second.second);
}
sort(d.begin(),d.end());
d.resize(unique(d.begin(),d.end()) - d.begin());
for(ll i = 0;i < N;i++){
arr[i].first = lower_bound(d.begin(),d.end(),arr[i].first) - d.begin() + 1;
arr[i].second.first = lower_bound(d.begin(),d.end(),arr[i].second.first) - d.begin() + 1;
arr[i].second.second = lower_bound(d.begin(),d.end(),arr[i].second.second) - d.begin() + 1;
}
sort(arr,arr + N);
deque<pair<ll,pair<ll,ll> > > waiting;
ll ans = -1e9;
for(ll i = 0;i < N;i++){
while(!waiting.empty() && waiting.front().first < arr[i].first){
ll bestC = -1e9;
if(waiting.front().second.first > 0){
bestC = rootBindtest -> rmq(0,waiting.front().second.first - 1).first;
}
if(bestC != -1e9 && bestC > waiting.front().second.second){
rootBind -> update(waiting.front().second.first,waiting.front().second.first + bestC);
}
ll bestB = -1e9;
if(waiting.front().second.second > 0){
bestB = rootCindtest -> rmq(0,waiting.front().second.second - 1).first;
}
if(bestB != -1e9 && bestB > waiting.front().second.first){
rootCind -> update(waiting.front().second.second,waiting.front().second.second + bestB);
}
rootBindtest -> update(waiting.front().second.first,waiting.front().second.second);
rootCindtest -> update(waiting.front().second.second,waiting.front().second.first);
waiting.pop_front();
}
if(arr[i].second.first > 0){
pair<ll,ll> maxiBind = rootBind -> rmq(arr[i].second.first + 1,3*N + 5);
if(maxiBind.first > 0){
ll B = maxiBind.second;
ll C = maxiBind.first - maxiBind.second;
if(C > arr[i].second.second){
ans = max(ans,d[arr[i].first - 1] + d[B - 1] + d[C - 1]); //need to minus 1 cos when I discretised, I made it 1-indexed to make it easier to implement
}
}
}
if(arr[i].second.second > 0){
pair<ll,ll> maxiCind = rootCind -> rmq(arr[i].second.second + 1,3*N + 5);
if(maxiCind.first > 0){
ll C = maxiCind.second;
ll B = maxiCind.first - maxiCind.second;
if(B > arr[i].second.first){
ans = max(ans,d[arr[i].first - 1] + d[B - 1] + d[C - 1]); //need to minus 1 cos when I discretised, I made it 1-indexed to make it easier to implement
}
}
}
waiting.push_back(arr[i]);
}
if(ans == -1e9) cout<<-1<<'\n';
else cout<<ans<<'\n';
}
