#include "fish.h"
#include <bits/stdc++.h>
//#pragma GCC optimize("O1,O2,O3,Ofast,unroll-loops")
#define ll long long
#define f first
#define s second
#define pb push_back
#define mp make_pair
#define o cout<<"BUG"<<endl;
#define FOR(i, j, n) for(int j = i; j < n; ++j)
#define forn(i, j, n) for(int j = i; j <= n; ++j)
#define nfor(i, j, n) for(int j = n; j >= i; --j)
#define all(v) v.begin(), v.end()
//#define ld long double
#define ull unsigned long long
using namespace std;
const int maxn=3e5+10,LOG=17,mod=1e9+7;
int block = 650, timer = 0;
const double eps = 1e-9;
//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define IOS ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define bt(i) (1 << (i))
//#define int ll
const long double inf=2e18;
#define y1 yy
#define pii pair <int, int>
int n, m, x[maxn], y[maxn], w[maxn];
ll a[3010][3010], pref[3010][3010], dp2[3010][3010];
ll dp[3010][3010], Dp[3010], ans;
long long max_weights(int N, int M, vector <int> X, vector <int> Y, vector <int> W)
{
n = N;
m = M;
forn(1, i, m)
{
x[i] = X[i-1]+1;
y[i] = Y[i-1]+1;
w[i] = W[i-1];
a[x[i]][y[i]] = w[i];
}
forn(1, i, n)
{
forn(1, j, n)
{
pref[i][j] = pref[i][j - 1] + a[i][j];
}
}
forn(1, i, n)
{
dp[0][i] = -inf;
}
forn(1, i, n)
{
ll tek = 0;
if(i >= 2)
{
forn(1, j, n)
{
tek = max(tek, dp[i-1][j] - pref[i-1][j]);
dp[i][j] = max(dp[i][j], pref[i-1][j] + tek);
}
}
// forn(1, j, n)
// cout << dp[i][j] << " ";
// cout << endl;
if(i >= 2)
{
tek = 0;
forn(1, j, n)
{
tek = max(tek, dp[i-2][j]);
dp[i][j] = max(dp[i][j], pref[i-1][j] + tek);
}
}
if(i >= 3)
{
tek = 0;
nfor(1, j, n)
{
dp[i][j] = max(dp[i][j], tek - pref[i-1][j]);
tek = max(tek, dp[i-2][j] + pref[i-1][j]);
}
}
if(i >= 3)
{
forn(1, j, n)
{
dp[i][j] = max(Dp[i-3] + pref[i-1][j], dp[i][j]);
}
}
tek = -inf;
nfor(1, j, n)
{
dp2[i][j] = max(dp2[i][j], tek - pref[i][j]);
// cout << i << " " << dp2[i][j] << " " << tek << endl;
tek = max(tek, max(dp2[i-1][j], dp[i-1][j]) + pref[i][j]);
Dp[i] = max(Dp[i], dp2[i][j] + pref[i+1][j]);
}
forn(1, j, n)
{
Dp[i] = max(Dp[i], dp[i][j] + pref[i+1][j]);
}
ans = max(ans, Dp[i]);
// cout << Dp[i] << " " << i << endl;
}
return ans;
}
