#include "fish.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vii;
typedef pair<int,int> pi;
typedef vector<pi> pii;
typedef tuple<int,int,int> tii;
typedef vector<ll> li;
typedef vector<li> lii;
#define REP(i,a,b) for(int i=a;i<b;i++)
#define F first
#define S second
#define PB push_back
#define MP make_pair
#define LSOne(s) ((s)&(-s))
ll INF=1e16+10;
int inf=1e9+10;
ll M=1e9+7;
long long max_weights(int n, int m, std::vector<int> X, std::vector<int> Y,
std::vector<int> W) {
vector<vector<ll>> dp(n,vector<ll>(2,0));
vector<ll> arr(n,0);
REP(i,0,m)arr[X[i]]+=(ll)W[i];
dp[0][0]=arr[1];
dp[1][0]=arr[0];dp[1][1]=arr[1];
if(n>2)dp[1][0]+=arr[2];
REP(i,2,n){
dp[i][1]=max(dp[i-1][0],dp[i-1][1]);
dp[i][0]=max(dp[i-1][0]-arr[i],dp[i-2][1]+arr[i-1]);
if(i!=n-1)dp[i][0]+=arr[i+1];
}
return max(dp[n-1][0],dp[n-1][1]);
}
