#include "fish.h"
#include <bits/stdc++.h>
using namespace std;
#define OPTM ios_base::sync_with_stdio(0); cin.tie(0);
#define INF int(1e9+7)
#define ln '\n'
#define ll long long
#define ull unsigned long long
#define ui unsigned int
#define us unsigned short
#define FOR(i,s,n) for (int i = s; i < n; i++)
#define FORR(i,n,s) for (int i = n; i > s; i--)
#define FORX(u, arr) for (auto u : arr)
#define PB push_back
#define in(v,x) (v.find(x) != v.end())
#define F first
#define S second
#define PII pair<int, int>
#define PLL pair<ll, ll>
#define UM unordered_map
#define US unordered_set
#define PQ priority_queue
#define ALL(v) v.begin(), v.end()
const ll LLINF = 1e18+1;
#define int long long
const int MAXN = 3e5+10;
int n,m;
vector<PII> p[MAXN];
vector<int> v1[MAXN];
vector<PII> v[MAXN], v2[MAXN];
vector<PII> dp[MAXN], dp1[MAXN], dp2[MAXN], dp3[MAXN];
int dp4, dp5;
US<int> vis1[MAXN];
void precalc() {
FOR(i,1,n+2) {
US<int> vis;
FORX(u,v[i]) {
if (!vis.count(u.F)) {
vis.insert(u.F);
v2[i].PB(u);
// v1[i].PB(u.F);
}
}
FORX(u,v[i+1]) {
if (!vis.count(u.F)) {
vis.insert(u.F);
v2[i].PB({u.F,0LL});
v1[i].PB(u.F);
}
}
FORX(u,v[i-1]) {
if (!vis.count(u.F)) {
vis.insert(u.F);
v2[i].PB({u.F,0LL});
v1[i].PB(u.F);
}
}
}
FOR(i,1,n+2) {
sort(ALL(v[i]));
sort(ALL(v1[i]));
sort(ALL(v2[i]));
}
FOR(i,1,n+2) {
int cur = 0LL;
FORX(u,v2[i]) {
p[i].PB({u.F,cur+u.S});
cur += u.S;
}
}
}
int locate(vector<PII> vec, int x, int t) {
if (t == 0) {
int ans = lower_bound(ALL(vec), make_pair(x,-LLINF))-vec.begin();
return ans == vec.size() ? -1 : ans;
}
else {
return upper_bound(ALL(vec), make_pair(x,LLINF))-vec.begin()-1;
}
}
void pr(vector<PII> vec) {
FORX(u,vec) cout << "(" << u.F << "," << u.S << ")" << " ";
cout << ln;
}
long long max_weights(int32_t N, int32_t M, std::vector<int32_t> X, std::vector<int32_t> Y, std::vector<int32_t> W) {
n = N; m = M;
FOR(i,0,m) {
if (!vis1[i+1].count(Y[i]+1)) {
vis1[i+1].insert(Y[i]+1);
v[X[i]+1].PB({Y[i]+1,W[i]});
}
}
FOR(i,1,n+1) {
v[i].PB({0LL,0LL});
if (!vis1[i].count(n)) {
vis1[i].insert(n);
v[i].PB({n,0LL});
}
}
precalc();
dp[1].PB({0LL,0LL});
dp1[1].PB({0LL,0LL});
dp2[1].PB({0LL,0LL});
int ma3 = 0LL;
int vn = v1[1].size();
FORR(pos,vn-1,-1) {
int j = v1[1][pos];
int idx = locate(p[2],j,1);
ma3 = max(ma3, p[2][idx].S);
dp3[1].PB({j,ma3});
}
sort(ALL(dp3[1]));
// pr(dp3[1]);
FOR(i,2,n+1) {
int vn = v1[i].size();
FORX(j,v1[i]) {
int idx = locate(p[i],j,1);
int idx1 = locate(p[i-1],j,1);
int idx2 = locate(dp2[i-1],j,1);
int idx3 = locate(dp3[i-1],j,0);
// cout << "idx3: " << j << " " << idx3 << ln;
int zero = max(dp4, dp5+p[i-1][idx1].S);
dp[i].PB({j, max(zero, dp2[i-1][idx2].S + p[i-1][idx1].S)});
dp1[i].PB({j, max(zero, dp3[i-1][idx3].S - p[i][idx].S)});
}
// cout << i << ": ";
// pr(dp[i]); pr(dp1[i]);
int ma2 = 0LL;
dp4 = 0LL, dp5 = 0LL;
FORX(j,v1[i]) {
int idx = locate(dp[i],j,1);
int idx1 = locate(p[i],j,1);
int idx2 = locate(dp[i-1],j,1);
ma2 = max(ma2, dp[i][idx].S - p[i][idx1].S);
dp2[i].PB({j,ma2});
dp4 = max(dp4, max(dp[i-1][idx2].S, dp1[i-1][idx2].S) + p[i][idx1].S);
dp5 = max(dp5, max(dp[i-1][idx2].S, dp1[i-1][idx2].S));
}
// if (i >= 5) return 0;
int ma3 = 0LL;
FORR(pos,vn-1,-1) {
int j = v1[i][pos];
int idx = locate(p[i+1],j,1);
ma3 = max(ma3, max(dp[i][pos].S, dp1[i][pos].S) + p[i+1][idx].S);
dp3[i].PB({j,ma3});
}
sort(ALL(dp3[i]));
}
int res = -LLINF;
FORX(u,dp[n]) res = max(res, u.S);
FORX(u,dp1[n]) res = max(res, u.S);
return res;
}
