#include "fish.h"
#ifdef NYAOWO
#include "grader.cpp"
#endif
#include <bits/stdc++.h>
#define For(i, a, b) for(int i = a; i <= b; i++)
#define Forr(i, a, b) for(int i = a; i >= b; i--)
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define sz(x) ((int)x.size())
#define eb emplace_back
#define int LL
using namespace std;
using i32 = int32_t;
using LL = long long;
using pii = pair<int, int>;
inline void chmax(int &x, int val) { x = max(x, val); }
const int MAXN = 100'000;
const int INF = 1e15;
int w[MAXN + 10];
int dp1[MAXN + 10]; // nothing
int dp2[MAXN + 10]; // selected
int dp3[MAXN + 10]; // (i-1) selected
long long max_weights(i32 N, i32 M, vector<i32> X, vector<i32> Y,
vector<i32> W) {
For(i, 0, M - 1) w[X[i]] += W[i];
dp1[0] = 0;
dp2[0] = 0;
dp3[0] = -INF;
For(i, 1, N - 1) {
dp1[i] = max(dp1[i - 1], dp3[i - 1]);
dp2[i] = max({dp1[i - 1] + w[i - 1], dp2[i - 1], dp3[i - 1]});
dp3[i] = dp2[i - 1] + w[i];
}
return max({dp1[N - 1], dp2[N - 1], dp3[N - 1]});
}
/*
5 4
0 2 5
1 1 2
4 4 1
3 3 3
8
*/
