#include "fish.h"
#include <bits/stdc++.h>
#define pb push_back
#define ll long long
using namespace std;
const int N = 3005;
ll p[N][N],dp[N][5],suff[N],pref[N],sfc[N][N],prc[N][N];
vector <int> v[N];
ll max_weights(int n, int m, vector<int> X, vector<int> Y, vector<int> W) {
for (int i = 0;i < m; i++){
X[i]++,Y[i]++;
p[X[i]][Y[i]] += W[i];
v[X[i] + 1].pb(Y[i]);
v[X[i] - 1].pb(Y[i]);
}
for (int j = 1; j <= n; j++)
for (int i = 1; i <= n; i++)
p[j][i] += p[j][i - 1];
for (int j = 1; j <= n; j++){
v[j].pb(0);
for (int a: v[j]){
dp[a][0] = suff[a] - p[j][a];
dp[a][1] = pref[a] + p[j - 1][a];
if (j >= 3){
dp[a][1] = max(dp[a][1], prc[j - 2][a] + p[j - 1][a]);
dp[a][1] = max(dp[a][1], sfc[j - 2][a]);
}
}
for (int a = n; a >= 0; a--)
suff[a] = max(suff[a+1],max(dp[a][0],dp[a][1]) + p[j + 1][a]);
pref[0] = dp[0][1] - p[j][0];
for (int a =1; a <= n; a++)
pref[a] = max(pref[a - 1],dp[a][1] - p[j][a]);
prc[j][0] = max(dp[0][0],dp[0][1]);
for (int a = 1; a <= n; a++)
prc[j][a] = max(prc[j][a - 1], max(dp[a][0],dp[a][1]));
for (int a = n; a >= 0; a--)
sfc[j][a] = max(sfc[j][a + 1],max(dp[a][0],dp[a][1]) + p[j + 1][a]);
}
ll ans = 0;
for (int a = 0; a <= n; a++)
ans=max({ans,dp[a][0],dp[a][1]});
return ans;
}
