#include<bits/stdc++.h>
//#define name "InvMOD"
#ifndef name
#include "fish.h"
#endif // name
using namespace std;
#define fi first
#define se second
//#define int long long
#define sz(v) (int)(v).size()
#define all(v) (v).begin(), (v).end()
#define dbg(x) "[" << #x " = " << (x) << "]"
using ll = long long;
namespace Subtask1{
bool ckSub(vector<int>& X){
for(int i = 0; i < sz(X); i++){
if(X[i] & 1) return false;
}
return true;
}
ll process(vector<int>& W){
ll answer = 0;
for(int i = 0; i < sz(W); i++){
answer += W[i];
}
return answer;
}
}
namespace Subtask2{
bool ckSub(vector<int>& X){
for(int i = 0; i < sz(X); i++){
if(X[i] > 1) return false;
}
return true;
}
ll process(int n, vector<int>& X, vector<int>& Y, vector<int>& W){
vector<vector<int>> row(2, vector<int>(n + 1));
vector<ll> sum(2, 0);
for(int i = 0; i < sz(X); i++){
row[X[i]][Y[i] + 1] = W[i];
sum[X[i]] += 1ll * W[i];
}
ll answer = max(sum[0], sum[1]), pref = 0;
if(n > 2){
for(int i = 1; i <= n; i++){
pref += row[0][i];
sum[1] -= row[1][i];
answer = max(answer, pref + sum[1]);
}
}
return answer;
}
}
namespace Subtask45{
bool ckSub(int n){
return n <= 300;
}
ll process(int n, vector<int>& X, vector<int>& Y, vector<int>& W){
vector<vector<int>> row(n + 1, vector<int>(n + 1));
for(int i = 0; i < sz(X); i++){
row[X[i] + 1][Y[i] + 1] = W[i];
}
vector<vector<ll>> pref(n + 1, vector<ll>(n + 1));
for(int i = 1; i <= n; i++){
for(int j = 1; j <= n; j++){
pref[i][j] = pref[i][j - 1] + row[i][j];
}
}
vector<vector<ll>> f(n + 1, vector<ll>(n + 1));
vector<vector<ll>> g(n + 1, vector<ll>(n + 1));
// f[i][j]: did not take from j + 1 -> n
// g[i][j]: take from j + 1 -> n
for(int i = 1; i <= n; i++){
for(int r = 0; r <= n; r++){
for(int l = 0; l <= n; l++){
f[i][r] = max(f[i][r], f[i - 1][l] + max(0ll, pref[i - 1][r] - pref[i - 1][l]));
f[i][r] = max(f[i][r], g[i - 1][l]);
}
//cout << i <<" " << r <<" " << dbg(f[i][r]) << "\n";
}
if(i > 1){
for(int r = 0; r <= n; r++){
for(int l = 0; l <= n; l++){
g[i][r] = max(g[i][r], f[i - 1][l] +
max(0ll, pref[i - 1][r] - pref[i - 1][l]) +
max(0ll, pref[i][l] - pref[i][r]));
g[i][r] = max(g[i][r], g[i - 1][l] + max(0ll, pref[i][l] - pref[i][r]));
}
//cout << i <<" " << r <<" " << dbg(g[i][r]) << "\n";
}
}
}
ll answer = 0;
for(int i = 1; i <= n; i++){
for(int j = 0; j <= n; j++){
answer = max(answer, f[i][j]);
answer = max(answer, g[i][j]);
}
}
return answer;
}
}
namespace Subtask6{
bool ckSub(int n){
return n <= 3000;
}
ll process(int n, vector<int>& X, vector<int>& Y, vector<int>& W){
vector<vector<int>> row(n + 1, vector<int>(n + 1));
for(int i = 0; i < sz(X); i++){
row[X[i] + 1][Y[i] + 1] = W[i];
}
vector<vector<ll>> pref(n + 1, vector<ll>(n + 1));
for(int i = 1; i <= n; i++){
for(int j = 1; j <= n; j++){
pref[i][j] = pref[i][j - 1] + row[i][j];
}
}
vector<vector<ll>> f(n + 1, vector<ll>(n + 1));
vector<vector<ll>> g(n + 1, vector<ll>(n + 1));
// f[i][j]: did not take from j + 1 -> n
// g[i][j]: take from j + 1 -> n
vector<vector<ll>> pMx(n + 1, vector<ll>(n + 1));
vector<vector<ll>> sMx(n + 1, vector<ll>(n + 1));
vector<vector<ll>> sgMx(n + 1, vector<ll>(n + 1));
vector<vector<ll>> pgMx(n + 1, vector<ll>(n + 1));
for(int i = 1; i <= n; i++){
for(int l = 0; l <= n; l++){
pMx[i - 1][l] = f[i - 1][l] - pref[i - 1][l];
pgMx[i - 1][l] = g[i - 1][l];
if(l > 0){
pMx[i - 1][l] = max(pMx[i - 1][l], pMx[i - 1][l - 1]);
pgMx[i - 1][l] = max(pgMx[i - 1][l], pgMx[i - 1][l - 1]);
}
}
for(int r = 0; r <= n; r++){
f[i][r] = max(f[i][r], pMx[i - 1][r] + pref[i - 1][r]);
f[i][r] = max(f[i][r], pgMx[i - 1][n]);
//cout << i <<" " << r <<" " << dbg(f[i][r]) << "\n";
}
if(i > 1){
for(int l = n; l >= 0; l--){
sMx[i - 1][l] = f[i - 1][l] + pref[i][l];
sgMx[i - 1][l] = g[i - 1][l] + pref[i][l];
if(l < n){
sMx[i - 1][l] = max(sMx[i - 1][l], sMx[i - 1][l + 1]);
sgMx[i - 1][l] = max(sgMx[i - 1][l], sgMx[i - 1][l + 1]);
}
}
for(int r = 0; r <= n; r++){
g[i][r] = max(g[i][r], sMx[i - 1][r] - pref[i][r]);
g[i][r] = max(g[i][r], sgMx[i - 1][r] - pref[i][r]);
//cout << i <<" " << r <<" " << dbg(g[i][r]) << "\n";
}
}
}
ll answer = 0;
for(int i = 1; i <= n; i++){
for(int j = 0; j <= n; j++){
answer = max(answer, f[i][j]);
answer = max(answer, g[i][j]);
}
}
return answer;
}
}
namespace Subtask8{
ll process(int n, vector<int>& X, vector<int>& Y, vector<int>& W){
vector<vector<pair<int ,ll>>> row(n + 1, vector<pair<int, ll>>(1, make_pair(0, 0)));
for(int i = 0; i < sz(X); i++){
row[X[i] + 1].push_back(make_pair(Y[i] + 1, W[i]));
}
vector<vector<ll>> pref(n + 1, vector<ll>(2, 0));
for(int i = 0; i <= n; i++){
row[i].push_back(make_pair(0, 0));
row[i].push_back(make_pair(n, 0));
sort(1 + all(row[i]));
vector<pair<int, ll>> comp;
for(int j = 0; j < sz(row[i]); j++){
if(!sz(comp)){
comp.push_back(row[i][j]);
}
else if(row[i][j].fi != comp.back().fi){
comp.push_back(row[i][j]);
}
else{
comp.back().se = row[i][j].se;
}
}
row[i] = comp;
pref[i].resize(sz(row[i]));
for(int j = 1; j < sz(row[i]); j++){
pref[i][j] = pref[i][j - 1] + row[i][j].se;
}
}
vector<vector<ll>> f(n + 1, vector<ll>(2, 0));
vector<vector<ll>> g(n + 1, vector<ll>(2, 0));
vector<vector<ll>> pMx(n + 1, vector<ll>(2, 0));
vector<vector<ll>> sMx(n + 1, vector<ll>(2, 0));
vector<vector<ll>> sgMx(n + 1, vector<ll>(2, 0));
vector<vector<ll>> pgMx(n + 1, vector<ll>(2, 0));
for(int i = 1; i <= n; i++){
f[i].resize(sz(row[i]));
g[i].resize(sz(row[i]));
pMx[i - 1].resize(sz(row[i - 1]));
pgMx[i - 1].resize(sz(row[i - 1]));
for(int l = 0; l < sz(row[i - 1]); l++){
pMx[i - 1][l] = f[i - 1][l] - pref[i - 1][l];
pgMx[i - 1][l] = g[i - 1][l];
if(l > 0){
pMx[i - 1][l] = max(pMx[i - 1][l], pMx[i - 1][l - 1]);
pgMx[i - 1][l] = max(pgMx[i - 1][l], pgMx[i - 1][l - 1]);
}
}
for(int r = 0, l = 0; r < sz(row[i]); r++){
if(r < sz(row[i]) - 1){
while(l < sz(row[i - 1]) && row[i - 1][l].fi < row[i][r + 1].fi) l++;
--l;
}
else l = sz(row[i - 1]) - 1;
f[i][r] = max(f[i][r], pMx[i - 1][l] + pref[i - 1][l]);
f[i][r] = max(f[i][r], pgMx[i - 1].back());
}
if(i > 1){
sMx[i - 1].resize(sz(row[i - 1]));
sgMx[i - 1].resize(sz(row[i - 1]));
for(int l = sz(row[i - 1]) - 1, r = sz(row[i]) - 1; l >= 0; l--){
if(row[i - 1][l].fi <= row[i][r].fi){
sMx[i - 1][l] = f[i - 1][l] + pref[i][r];
sgMx[i - 1][l] = g[i - 1][l] + pref[i][r];
}
while(r >= 0 && row[i][r].fi >= row[i - 1][l].fi) r--;
if(l < sz(row[i - 1]) - 1){
sMx[i - 1][l] = max(sMx[i - 1][l], sMx[i - 1][l + 1]);
sgMx[i - 1][l] = max(sgMx[i - 1][l], sgMx[i - 1][l + 1]);
}
}
for(int l = 0, r = 0; l < sz(row[i]); l++){
while(r < sz(row[i - 1]) && row[i - 1][r].fi <= row[i][l].fi) r++;
r = max(r - 1, 0);
g[i][l] = max(g[i][l], sMx[i - 1][r] - pref[i][l]);
g[i][l] = max(g[i][l], sgMx[i - 1][r] - pref[i][l]);
}
}
}
ll answer = 0;
for(int i = 1; i <= n; i++){
for(int j = 0; j < sz(row[i]); j++){
answer = max(answer, f[i][j]);
answer = max(answer, g[i][j]);
}
}
return answer;
}
}
ll max_weights(int n, int m, vector<int> X, vector<int> Y, vector<int> W){
return Subtask8::process(n, X, Y, W);
}
