#include<bits/stdc++.h>
using namespace std;
const int maxn = 150000;
const int maxval = 450000;
int n, l, r, m, c, res = -1;
struct beaver{
int X, Y, Z;
};
beaver a[maxn];
vector<int> v;
struct str{
int max, min;
inline str(){
max = -1;
min = maxval + 10;
}
};
str operator + (const str& x, const str& y){
str ans;
ans.max = max(x.max, y.max);
ans.min = min(x.min, y.min);
return ans;
}
class segment_tree{
private:
vector<str> st;
void update(int id, int l, int r, int i, int val){
if (i > r || i < l) return;
if (l == r){
st[id].max = max(st[id].max, val);
st[id].min = min(st[id].min, val);
return;
}
int mid = (l + r) >> 1;
update(id * 2, l, mid, i, val);
update(id * 2 + 1, mid + 1, r, i, val);
st[id] = st[id * 2] + st[id * 2 + 1];
return;
}
int get(int id, int l, int r, int u, int v, bool maxx){
if (l > v || r < u){
if (maxx) return -1;
return maxval + 1;
}
if (l >= u && r <= v){
if (maxx) return st[id].max;
return st[id].min;
}
int mid = (l + r) >> 1;
if (maxx) return max(get(id * 2, l, mid, u, v, maxx), get(id * 2 + 1, mid + 1, r, u, v, maxx));
return min(get(id * 2, l, mid, u, v, maxx), get(id * 2 + 1, mid + 1, r, u, v, maxx));
}
public:
inline segment_tree(){
st.resize(maxval << 2);
}
void update(int i, int val){
update(1, 1, maxval, i, val);
}
int getmax(int u, int v){
return get(1, 1, maxval, u, v, 1);
}
int getmin(int u, int v){
return get(1, 1, maxval, u, v, 0);
}
} st1, st2;
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> n;
for (int i = 0; i < n; ++i){
cin >> a[i].X >> a[i].Y >> a[i].Z;
v.push_back(a[i].X);
v.push_back(a[i].Y);
v.push_back(a[i].Z);
}
sort(v.begin(), v.end());
auto it = unique(v.begin(), v.end());
v.erase(it, v.end());
for (int i = 0, j = 0; i < n; ++i){
a[i].X = lower_bound(v.begin(), v.end(), a[i].X) - v.begin() + 1;
a[i].Y = lower_bound(v.begin(), v.end(), a[i].Y) - v.begin() + 1;
a[i].Z = lower_bound(v.begin(), v.end(), a[i].Z) - v.begin() + 1;
while (a[j].X != a[i].X){
st1.update(a[j].Y, a[j].Z);
c = st1.getmax(1, a[j].Y - 1);
if (c > a[j].Z){
st2.update(a[j].Y, c);
}
l = a[j].Y + 1;
r = maxval;
int ans = -1;
while (l <= r){
m = (l + r) >> 1;
if (st1.getmin(m, maxval) < a[j].Z){
ans = m;
l = m + 1;
}
else r = m - 1;
}
if (ans != -1){
st2.update(m, a[j].Z);
}
j++;
}
l = a[i].Y + 1;
r = maxval;
int ans = -1;
while (l <= r){
m = (l + r) >> 1;
if (st2.getmax(m, maxval) > a[i].Z){
ans = m;
l = m + 1;
}
else r = m - 1;
}
if (ans != -1){
res = max(res, v[a[i].X - 1] + v[ans - 1] + v[st2.getmax(ans, maxval) - 1]);
}
}
cout << res;
}
