#include "fish.h"
#include <bits/stdc++.h>
using namespace std;
//#define int long long
#define ll long long
#define fi first
#define se second
#define pii pair<int, int>
const int MAX = 3000010;
int n, m;
vector <int> vx, vy, w;
ll dp[MAX][5][2];
int mat[MAX][5];
ll max_weights(int N, int M, vector<int> X, vector<int> Y, vector<int> W) {
n = N, m = M, vx = X, vy = Y, w = W;
for (int i = 0; i < m; i++) {
vx[i]++;
vy[i]++;
mat[vx[i]][vy[i]] += w[i];
}
for (int i = 2; i <= n; i++) {
for (int j = 0; j <= 1; j++) dp[i][j][0] = max(dp[i - 1][j][0], dp[i - 1][j][1]);
for (int j = 0; j <= 1; j++) dp[i][j][1] = max(dp[i - 1][j][0], dp[i - 1][j][1]);
ll maxx = 0;
for (int j = 1; j >= 0; j--) {
maxx = max(maxx, max(dp[i - 1][j][0], dp[i - 1][j][1]));
dp[i][j][0] = max(dp[i][j][0], maxx);
maxx += mat[i][j];
}
maxx = 0;
for (int j = 0; j <= 1; j++) {
maxx += mat[i - 1][j];
maxx = max(maxx, dp[i - 1][j][1]);
dp[i][j][1] = max(dp[i][j][1], maxx);
}
for (int j = 0; j <= 1; j++) dp[i][j][0] = max(dp[i][j][0], dp[i][j][1]);
}
ll ret = 0;
for (int i = 0; i <= n; i++) ret = max(ret, max(dp[n][i][0], dp[n][i][1]));
return ret;
}
