#include <bits/stdc++.h>
#define int ll
using namespace std;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define rng(i,c,n) for(int i=c;i<n;i++)
#define fi first
#define se second
#define pb push_back
#define sz(a) (int)a.size()
#define vec(...) vector<__VA_ARGS__>
typedef long long ll;
using pii=pair<int,int>;
using vi=vec(int);
void print(){cout<<"\n";}
template<class H,class ...T>
void print(const H&v,const T...u){cout<<v<<' ',print(u...);}
// e
const int inf=1e11;
using tpii=pair<int,pii>;
#define all(a) a.begin(),a.end()
const int nax=800011;
int nseg;
int seg[nax];
void build(int n){
nseg=1;
while(nseg<=n){
nseg*=2;
}
}
void upd(int pos,int val,int v,int l,int r){
int m=(l+r)/2;
if(l==r-1){
// cout<<v<<" "<<val<<"\n";
seg[v]=val;
return;
}
if(pos<m){
upd(pos,val,v*2+1,l,m);
}else{
upd(pos,val,v*2+2,m,r);
}
seg[v]=max(seg[v*2+1],seg[v*2+2]);
}
void upd(int pos,int val){
upd(pos,val,0,0,nseg);
}
int prod(int v,int l,int r,int _l,int _r){
if(l>=_r or r<=_l){
return -inf;
}
if(_l<=l and r<=_r){
// cout<<"\n";
// cout<<l<<" "<<r<<" "<<seg[v]<<"\n";
return seg[v];
}
int m=(l+r)>>1;
return max(prod(v*2+1,l,m,_l,_r),prod(v*2+2,m,r,_l,_r));
}
int prod(int l,int r){
return prod(0,0,nseg,l,r);
}
signed main(){
ios::sync_with_stdio(0),
cin.tie(0);
int n;
cin>>n;
vec(tpii) a(n);
for(int i=0;i<n;i++){
cin>>a[i].fi>>a[i].se.fi>>a[i].se.se;
}
vi zs;
rep(i,n){
zs.pb(a[i].fi);
}
sort(zs.begin(),zs.end());
rep(i,n){
a[i].fi=lower_bound(all(zs),a[i].fi)-zs.begin();
}
build(n);
vec(vec(pii)) qols(sz(zs)+11);
rep(t,2){
sort(all(a),[&](tpii l,tpii r){
return l.se.fi<r.se.fi;
});
vec(multiset<int>) rbts(sz(zs));
rep(i,sz(zs)){
upd(i,-inf);
}
for(int i=0;i<n;i++){
rbts[a[i].fi].insert(a[i].se.se);
}
for(int i=0;i<sz(zs);i++){
int val=(sz(rbts[i])?*prev(rbts[i].end()):-inf);
// cout<<val<<" ";
upd(i,val);
}
// cout<<prod(0,4)<<"\n";
for(int i=n-1;i>=0;i--){
vec(tpii) delay;
{
pii p=a[i].se;
// cout<<a[i].fi<<" "<<a[i].se.fi<<" "<<a[i].se.se<<"\n";
int z=a[i].fi;
delay.pb({z,p});
rbts[z].erase(rbts[z].find(p.se));
int val=(sz(rbts[z])?*prev(rbts[z].end()):-inf);
upd(z,val);
while(i-1>=0 and a[i-1].se.fi==p.fi){
pii np=a[i-1].se;
int nz=a[i-1].fi;
// upd(a[i-1].fi,-inf);
rbts[nz].erase(rbts[nz].find(np.se));
int val=(sz(rbts[nz])?*prev(rbts[nz].end()):-inf);
upd(nz,val);
delay.pb({a[i-1].fi,np});
i-=1;
}
}
// int val=prod(0,a[i].fi);
// // return maxY in Zs an Xs smaller than me
for(auto tp:delay){
int z=tp.fi;
int x=tp.se.fi;
int y=tp.se.se;
int val=prod(0,z+1);
// cout<<z<<" "<<x<<" "<<y<<"\n";
// cout<<val<<"\n";
if(val>y){
// cout<<"ho\n";
if(!t){
qols[z+1].pb({x,val});
}
else{
qols[z+1].pb({val,x});
}
// + 1 because p.se can't use this
}
}
}
rep(i,n){
swap(a[i].se.se,a[i].se.fi);
}
}
vec(pii) rbe(sz(zs)+11);
pii fip={-inf,-inf};
for(int i=0;i<sz(zs);i++){
// cout<<zs[i]<<"\n";
for(auto p:qols[i]){
// cout<<p.fi<<" "<<p.se<<"\n";
if(p.fi>fip.fi){
fip=p;
}else if(p.fi==fip.fi and p.se>fip.se){
fip=p;
}
}
rbe[i]=fip;
}
int ans=-1;
for(int i=0;i<n;i++){
pii p=a[i].se;
int z=a[i].fi;
if(rbe[z].fi>p.fi and rbe[z].se>p.se){
ans=max(ans,zs[a[i].fi]+rbe[z].fi+rbe[z].se);
}
}
print(ans);
//
return 0;
}
