#include "fish.h"
#include <bits/stdc++.h>
using namespace std;
#define ll long long
bool deb = false;
int n, m;
vector<int> x, y;
vector<ll> w;
void dbg(vector<int> xx) {
if (!deb) return;
cout << "DBG: ";
for (auto x: xx) cout << x << " ";
cout << "\n";
}
ll max_weights(int N, int M, std::vector<int> X, std::vector<int> Y, std::vector<int> W) {
n = N;
m = M;
x = X;
y = Y;
for (auto x: W) w.push_back(x);
vector<ll> arr(n);
for (int i = 0; i < m; i++) {
arr[x[i]] += w[i];
}
vector<ll> dp(n, 0);
ll ans = arr[0];
for (int i = 1; i < n; i++) {
dp[i] = dp[i-1];
if (i >= 2) {
dp[i] = max(dp[i], dp[i-2] + arr[i-1]);
}
if (i >= 3) {
dp[i] = max(dp[i], dp[i-3] + arr[i-2] + arr[i-1]);
}
if (i >= 4)
ans = max({ans, dp[i], dp[i-1] + arr[i]});
}
return ans;
}
