#include<bits/stdc++.h>
using namespace std;
const long long N=4*1e5,value=1e18;
struct grp{
long long x,y,z;
} p[2*100010];
struct node{
long long mn=value,mx=-value;
} st[8*100010];
long long i,n,j=0,ans=-1,pos=1;
vector<long long> vec;
bool flag=0;
node merge_node(const node& A,const node& B){
if (A.mx<0) return B;
if (B.mx<0) return A;
return {min(A.mn,B.mn),max(A.mx,B.mx)};
}
void update(long long id,long long l,long long r,long long u,long long x){
if (r<u||u<l) return;
if (l>=r){
st[id].mn=min(st[id].mn,x);
st[id].mx=max(st[id].mx,x);
return;
}
long long mid=(l+r)/2;
update(2*id,l,mid,u,x);
update(2*id+1,mid+1,r,u,x);
st[id]=merge_node(st[2*id],st[2*id+1]);
}
node get(long long id,long long l,long long r,long long u,long long v){
if (u>v) return {value,-value};
if (r<u||v<l) return {value,-value};
if (u<=l&&r<=v) return st[id];
long long mid=(l+r)/2;
return merge_node(get(2*id,l,mid,u,v),get(2*id+1,mid+1,r,u,v));
}
void calibrate(long long idx,long long val){
if (idx<pos){
long long x=get(1,1,N,1,pos-1).mx;
update(1,1,N,idx,val);
long long new_x=get(1,1,N,1,pos-1).mx;
if (new_x>x){
long long l=1,r=N;
while (l<=r){
long long mid=(l+r)/2;
long long ca1=get(1,1,N,mid,N).mn;
if (new_x>ca1) l=mid+1;
else r=mid-1;
}
if (r<1||r>N) return;
pos=r;
}
}
else{
long long old_x=get(1,1,N,pos,N).mn,old_mx=get(1,1,N,1,idx).mx;
update(1,1,N,idx,val);
long long new_x=get(1,1,N,pos,N).mn,new_mx=get(1,1,N,1,idx).mx;
//if (i==3) cout<<old_mx<<" "<<new_mx;
if (old_x>new_x){
if (get(1,1,N,idx,N).mn<get(1,1,N,1,idx-1).mx) pos=idx;
}
else if (old_mx<new_mx){
//cout<<10;
long long l=1,r=N;
while (l<=r){
long long mid=(l+r)/2;
long long ca1=get(1,1,N,mid,N).mn;
if (new_mx>ca1) l=mid+1;
else r=mid-1;
}
if (r<1||r>N) return;
pos=r;
}
}
}
signed main(){
//freopen("team.inp","r",stdin);
//freopen("team.out","w",stdout);
cin.tie(0)->sync_with_stdio(0);
cin>>n;
for (i=1;i<=n;i++) cin>>p[i].x>>p[i].y>>p[i].z;
sort(p+1,p+n+1,[](const grp& A,const grp& B){
return A.x<B.x;
});
long long j=0;
for (i=1;i<=n;i++){
vec.push_back(p[i].y);
}
sort(vec.begin(),vec.end());
vec.erase(unique(vec.begin(),vec.end()),vec.end());
for (i=1;i<=n;i++){
p[i].y=lower_bound(vec.begin(),vec.end(),p[i].y)-vec.begin()+1;
}
pos=1;
for (i=1;i<=n;i++){
//cout<<p[i].x<<" "<<p[i].y<<" "<<p[i].z<<"\n";
if (p[i].x!=p[i-1].x){
while (j+1<i){
j++;
calibrate(p[j].y,p[j].z);
}
}
//cout<<pos<<" ";
if (p[i].y>=pos) continue;
long long x=get(1,1,N,1,pos-1).mx;
if (x>get(1,1,N,pos,N).mn){
if (x>p[i].z) ans=max(ans,p[i].x+vec[pos-1]+x);
}
}
cout<<ans;
}
