#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
//#include<bits/extc++.h>
//__gnu_pbds
vector<int> Y;
vector<int> Z;
vector<int> X;
int main(){
ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0);
int n;cin>>n;
X.resize(n);
Y.resize(n);
Z.resize(n);
vector<int> w(n);
for(int i=0;i<n;i++) cin>>X[i]>>Y[i]>>Z[i];
for(int i=0;i<n;i++) {w[i]=i;}
sort(w.begin(),w.end(),[&](const int a,const int b){return Y[a]<Y[b];});
int ans = -1;
for(int i=0;i<n;i++){
int l = 0;int r = n;
while(r-l>1){
int mid = (l+r)/2;
if(Y[w[mid]]>Y[i]) r = mid;
else l = mid;
}
int maxn = -1e9;
for(int j=0;j<r;j++){
if(X[w[j]]>=X[i]) continue;
maxn = max(maxn,Z[w[j]]);
}
for(int j=r;j<n;j++){
if(X[w[j]]>=X[i]) continue;
if(maxn>Z[i] && maxn>Z[w[j]]){
ans = max(ans,maxn+X[i]+Y[w[j]]);
}
maxn = max(maxn,Z[w[j]]);
}
}
cout<<ans<<"\n";
return 0;
}
