#include "fish.h"
#include <vector>
#include <bits/stdc++.h>
using namespace std;
//#define int long long
long long max_weights(int N, int M, std::vector<int> X, std::vector<int> Y, std::vector<int> W) {
// y[i] = 0
vector<vector<long long>> dp(N, vector<long long>(3));
vector<long long> a(N, 0);
for (int i = 0; i < M; i++) a[X[i]] = W[i];
dp[0][0] = dp[1][0] = 0;
dp[0][1] = a[0]; dp[1][1] = a[1];
for (int i = 2; i < N; i++) {
dp[i][0] = max({dp[i - 1][0], dp[i - 1][1], dp[i - 1][2]});
dp[i][1] = max({dp[i - 1][0] + a[i], dp[i - 1][1] - a[i - 1] + a[i], dp[i - 2][1] + a[i]});
if (i != N - 1) dp[i][2] = max({dp[i - 1][1] + a[i]});
}
long long ans = 0;
for (int i = 0; i < N; i++) ans = max(ans, max({dp[i][0], dp[i][1], dp[i][2]}));
return ans;
}
