#include<bits/stdc++.h>
using namespace std;
#ifndef BADGNU
#pragma GCC target("sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
#endif
#pragma GCC optimize("Ofast,unroll-loops,fast-math,O3")
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#define ll long long
#define int ll
#define ld long double
#define y1 cheza
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
template<class T> using ordered_set = tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;
template<class T> using ordered_multiset = tree<T,null_type,less_equal<T>,rb_tree_tag,tree_order_statistics_node_update>;
const int N=2100;
const int M=5001;
const int B=447;
const int mod=998244353;
const ll INF=1e18;
const int dx[]={1,-1,0,0};
const int dy[]={0,0,1,-1};
const double eps=1e-6;
int n;
struct pt{
ld x,y;
int w;
};
pt a[N];
int pref[N];
void test(){
cin>>n;
for(int i=1;i<=n;i++){
cin>>a[i].x>>a[i].y>>a[i].w;
}
sort(a+1,a+n+1,[](pt x,pt y){
if(x.x==y.x){
if(x.y==y.y){
return x.w<y.w;
}
return x.y<y.y;
}
return x.x<y.x;
});
for(int i=1;i<=n;i++){
pref[i]=pref[i-1]+a[i].w;
}
int ans=0;
int mn=0;
for(int i=1;i<=n;i++){
mn=min(mn,pref[i-1]);
ans=max(ans,pref[i]-mn);
}
cout<<ans<<'\n';
}
/*
*/
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
// cout.tie(nullptr);
int t2=1;
// cin>>t2;
for(int i=1;i<=t2;i++){
test();
}
}
