#include "fish.h"
#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 3e5 + 2;
const long long INF = 1e18;
unordered_map<int, long long> costCell[MAX_N], dp[MAX_N], dpLower[MAX_N], spX[MAX_N], maxPref1[MAX_N], maxSuf2[MAX_N], maxPref3[MAX_N];
vector <int> ys[MAX_N];
long long max_weights( int n, int m, vector <int> X, vector <int> Y, vector <int> W ) {
for ( int i = 0; i < m; i++ ) {
X[i]++;
Y[i]++;
costCell[X[i]][Y[i]] = W[i];
ys[X[i] - 1].push_back( Y[i] );
ys[X[i] + 1].push_back( Y[i] );
}
ys[0].clear();
ys[n + 1].clear();
for ( int x = 0; x <= n + 1; x++ )
ys[x].push_back( 0 );
for ( int x = 1; x <= n; x++ ) {
sort( ys[x].begin(), ys[x].end() );
ys[x].resize( unique( ys[x].begin(), ys[x].end() ) - ys[x].begin() );
}
for ( int x = 1; x <= n; x++ ) {
vector<int> yss;
for ( int i = 0; i < ys[x].size(); i++ )
yss.push_back( ys[x][i] );
for ( int i = 0; i < ys[x - 1].size(); i++ )
yss.push_back( ys[x - 1][i] );
for ( int i = 0; i < ys[x + 1].size(); i++ )
yss.push_back( ys[x + 1][i] );
sort( yss.begin(), yss.end() );
yss.resize( unique( yss.begin(), yss.end() ) - yss.begin() );
for ( int i = 1; i < yss.size(); i++ )
spX[x][yss[i]] = spX[x][yss[i - 1]] + costCell[x][yss[i]];
}
dp[0][0] = dpLower[0][0] = 0;
for ( int x = 1; x <= n + 1; x++ ) {
for ( int i = 0; i < ys[x].size(); i++ ) {
int crtY = ys[x][i];
dp[x][crtY] = dpLower[x][crtY] = -INF;
if ( x >= 1 ) {
auto lower = upper_bound( ys[x - 1].begin(), ys[x - 1].end(), crtY );
auto upper = lower_bound( ys[x - 1].begin(), ys[x - 1].end(), crtY );
if ( lower != ys[x - 1].begin() ) {
lower--;
int prevY = *lower;
dpLower[x][crtY] = max( dpLower[x][crtY], maxPref1[x - 1][prevY] + spX[x - 1][crtY] );
dp[x][crtY] = max( dp[x][crtY], maxPref1[x - 1][prevY] + spX[x - 1][crtY] );
}
if ( upper != ys[x - 1].end() ) {
int prevY = *upper;
dp[x][crtY] = max( dp[x][crtY], maxSuf2[x - 1][prevY] - spX[x][crtY] );
}
}
if ( x >= 2 ) {
auto lower = upper_bound( ys[x - 2].begin(), ys[x - 2].end(), crtY );
auto upper = lower_bound( ys[x - 2].begin(), ys[x - 2].end(), crtY );
if ( lower != ys[x - 2].begin() ) {
lower--;
int prevY = *lower;
dpLower[x][crtY] = max( dpLower[x][crtY], maxPref3[x - 2][prevY] + spX[x - 1][crtY] );
dp[x][crtY] = max( dp[x][crtY], maxPref3[x - 2][prevY] + spX[x - 1][crtY] );
}
if ( upper != ys[x - 2].end() ) {
int prevY = *upper;
dpLower[x][crtY] = max( dpLower[x][crtY], maxSuf2[x - 2][prevY] );
dp[x][crtY] = max( dp[x][crtY], maxSuf2[x - 2][prevY] );
}
}
maxPref1[x][crtY] = dpLower[x][crtY] - spX[x][crtY];
maxSuf2[x][crtY] = dp[x][crtY] + spX[x + 1][crtY];
maxPref3[x][crtY] = dpLower[x][crtY];
}
for ( int i = 1; i < ys[x].size(); i++ ) {
maxPref1[x][ys[x][i]] = max( maxPref1[x][ys[x][i]], maxPref1[x][ys[x][i - 1]] );
maxPref3[x][ys[x][i]] = max( maxPref3[x][ys[x][i]], maxPref3[x][ys[x][i - 1]] );
}
for ( int i = ys[x].size() - 2; i >= 0; i-- )
maxSuf2[x][ys[x][i]] = max( maxSuf2[x][ys[x][i]], maxSuf2[x][ys[x][i + 1]] );
}
/*for ( int x = 0; x <= n + 1; x++ ) {
for ( int i = 0; i < ys[x].size(); i++ )
printf( "(%d %lld) ", ys[x][i], dp[x][i] );
printf( "\n" );
}*/
return dp[n + 1][0];
}
