#include<bits/stdc++.h>
using namespace std;
#define int long long
#define fi first
#define se second
#define pb push_back
signed main()
{
ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
// freopen("input.000","r",stdin);
// freopen("output.000","w",stdout);
// srand((unsigned)time(NULL));
// rand()
static int n,i,max_x[150005],max_y[150005],max_x_global,max_y_global,cur_num,cur_id,j,ans;
static pair<pair<int,int>,int> x[150005];
static pair<int,pair<int,int>> y[150005];
cin>>n;
for (i=1;i<n+1;i++) cin>>x[i].fi.fi>>x[i].fi.se>>x[i].se;
sort(x+1,x+n+1);
max_x[0]=max_y[0]=0;
for (i=1;i<n+1;i++)
{
max_x[i]=max(max_x[i-1], x[i].fi.fi);
max_y[i]=max(max_y[i-1], x[i].fi.se);
}
while (max_x[n]==x[n].fi.fi and max_y[n]==x[n].fi.se and n>0) n--;
if (n<3)
{
cout<<-1;return 0;
}
for (i=1;i<n+1;i++) y[i]={x[i].se,{x[i].fi.fi, x[i].fi.se}};
sort(y+1,y+n+1);
// for (i=1;i<n+1;i++) cout<<y[i].fi<<y[i].se.fi<<y[i].se.se<<"\n";
max_x_global=max_y_global=0;
cur_num=y[1].fi;
cur_id=1;
ans=-1;
for (i=1;i<n+1;i++)
{
if (cur_num < y[i].fi)
{
for (j=cur_id; j<i; j++)
{
max_x_global=max(max_x_global,y[j].se.fi);
max_y_global=max(max_y_global,y[j].se.se);
}
cur_id=i;
cur_num=y[i].fi;
}
if (y[i].se.fi < max_x_global and y[i].se.se < max_y_global)
ans=max(ans,y[i].fi + max_x_global + max_y_global);
}
cout<<ans;
}
