#include "fish.h"
#include <bits/stdc++.h>
#include <vector>
using namespace std;
long long zero[101010], full[101010];
vector< pair<int, long long> > ylist[101010];
vector< long long > sum[101010], dp[2][101010];
long long max_weights(int N, int M, std::vector<int> X, std::vector<int> Y, std::vector<int> W) {
for (int i = 0; i < M; i++) {
X[i] += 1;
Y[i] += 1;
ylist[X[i]].push_back({Y[i], W[i]});
ylist[X[i] - 1].push_back({Y[i], 0});
ylist[X[i] + 1].push_back({Y[i], 0});
}
for (int i = 0; i <= N + 1; i++) {
ylist[i].push_back({0, 0});
ylist[i].push_back({N, 0});
sort(ylist[i].begin(), ylist[i].end());
sum[i].push_back(0);
for (int j = 1; j < ylist[i].size(); j++) {
sum[i].push_back(sum[i].back() + ylist[i][j].second);
}
}
for (int i = 0; i <= N + 1; i++) {
for (int j = 0; j < ylist[i].size(); j++) dp[0][i].push_back(0);
for (int j = 0; j < ylist[i].size(); j++) dp[1][i].push_back(0);
}
for (int j = 0; j < ylist[0].size(); j++) dp[0][0].push_back(-1e18);
for (int j = 0; j < ylist[0].size(); j++) dp[1][0].push_back(-1e18);
full[0] = -1e18;
for (int i = 2; i <= N + 1; i++) {
long long val0 = 0, val1 = 0;
for (int k = 1; k < ylist[i - 1].size() - 1; k++) {
val0 = max(val0, dp[0][i - 1][k] - sum[i - 1][k]);
val1 = max(val1, dp[1][i - 1][k] + sum[i][k]);
}
zero[i] = max(val1, max(zero[i - 1], full[i - 1] + sum[i][ylist[i].size() - 1]));
for (int j = 1; j < ylist[i].size() - 1; j++) {
dp[1][i][j] = max(dp[1][i][j], val1 - sum[i][j]);
dp[1][i][j] = max(dp[1][i][j], full[i - 1] + sum[i][ylist[i].size() - 1] - sum[i][j]);
}
for (int j = 1; j < ylist[i].size() - 1; j++) {
int k = lower_bound(ylist[i - 1].begin(), ylist[i - 1].end(), make_pair(ylist[i][j].first, 0LL))
- ylist[i - 1].begin();
dp[0][i][j] = max(dp[0][i][j], val0 + sum[i - 1][k]);
dp[0][i][j] = max(dp[0][i][j], zero[i - 2] + sum[i - 1][k]);
dp[0][i][j] = max(dp[0][i][j], full[i - 2] + sum[i - 1][ylist[i - 1].size() - 1]);
}
long long val2 = 0;
int l = 0;
for (int j = 1; j < ylist[i].size() - 1; j++) {
int k = lower_bound(ylist[i - 1].begin(), ylist[i - 1].end(), make_pair(ylist[i][j].first, 0LL))
- ylist[i - 1].begin();
while (l < ylist[i - 2].size() && ylist[i - 2][l].first <= j) {
val2 = max(val2, dp[1][i - 2][l]);
l++;
}
dp[0][i][j] = max(dp[0][i][j], val2 + sum[i - 1][k]);
}
long long val3 = 0;
l = ylist[i - 2].size() - 1;
for (int j = ylist[i].size() - 1; j >= 1; j--) {
int k = lower_bound(ylist[i - 1].begin(), ylist[i - 1].end(), make_pair(ylist[i][j].first, 0LL))
- ylist[i - 1].begin();
while (l >= 0 && ylist[i - 2][l].first >= j) {
val3 = max(val3, dp[1][i - 2][l] + sum[i - 1][k]);
l--;
}
dp[0][i][j] = max(dp[0][i][j], val3);
}
full[i] = max(val0 + sum[i - 1][ylist[i - 1].size() - 1], full[i - 1]);
full[i] = max(full[i], zero[i - 2] + sum[i - 1][ylist[i - 1].size() - 1]);
full[i] = max(full[i], full[i - 2] + sum[i - 1][ylist[i - 1].size() - 1]);
full[i] = max(full[i], val2 + sum[i - 1][ylist[i - 1].size() - 1]);
}
long long res = 0;
res = zero[N + 1];
return res;
}
