#include "fish.h"
#define ll long long
#include <bits/stdc++.h>
using namespace std;

const int N=300010;
int x[N],y[N],w[N];
ll dp[N][2],f[N],g[N];
vector <int> v[N];
bool cmp (int a,int b) {return y[a]<y[b];}
ll max_weights (int n,int m,vector <int> X,vector <int> Y,vector <int> W) {
	for (int i=0;i<m;i++) {x[i+1]=X[i]+1,y[i+1]=Y[i],w[i+1]=W[i];v[X[i]+1].push_back(i+1);}
	for (int i=1;i<=n;i++) {
		f[i]=g[i]=max(f[i-1],g[i-1]);
		sort(v[i].begin(),v[i].end(),cmp);
		int l1=v[i-1].size(),l2=v[i].size(),c1=l1;
		ll mx=max(f[i-2],g[i-2]);
		if (i!=1) {
			for (int j=l2-1;j>=0;j--) {
				while (c1&&y[v[i-1][c1-1]]>y[v[i][j]]) {mx=max(mx,dp[v[i-1][--c1]][0]);}
				dp[v[i][j]][0]=mx+w[v[i][j]];
				f[i]=max(f[i],dp[v[i][j]][0]);
			}
		}
		c1=0,mx=f[i-1];
		if (i!=n) {
			for (int j=0;j<l2;j++)  {
				while (c1<l1&&y[v[i-1][c1]]<y[v[i][j]]) {mx=max(mx,dp[v[i-1][c1++]][1]);}
				dp[v[i][j]][1]=mx+w[v[i][j]];
				g[i]=max(g[i],dp[v[i][j]][1]);
			}
		}
	}
	ll res=0;
	for (int i=1;i<=m;i++) {
		res=max(res,max(dp[i][0],dp[i][1]));
	}
	return res;
}