#include <bits/stdc++.h>
#include "fish.h"
using namespace std;
#define pb push_back
#define fi first
#define se second
const int nax = 3e3+5;
vector<long long> tab[nax];
long long max_weights(int N, int M, std::vector<int> X, std::vector<int> Y,
std::vector<int> W) {
int n=N;
int m=M;
int grid[n+1][n+1];
memset(grid,0,sizeof grid);
long long pre[n+1][n+1];
memset(pre,0,sizeof pre);
for (int i = 0; i < m; ++i)
{
grid[X[i]][Y[i]+1]+=W[i];
}
for (int i = 0; i < n; ++i)
{
for (int j = 0; j <= n; ++j)
{
pre[i][j]=(j ? pre[i][j-1] : 0)+grid[i][j];
}
}
long long dp[n+1][n+1][2];
memset(dp,0,sizeof dp);
long long ans=0;
for (int i = 1; i < n; ++i)
{
for (int j = 0; j <= n; ++j)
{
for (int k = 0; k <= n; ++k)
{
if(k<j){
dp[i][j][1]=max(dp[i][j][1],dp[i-1][k][1]+pre[i-1][j]-pre[i-1][k]);
dp[i][j][1]=max(dp[i][j][1],dp[i-1][0][0]);
}else if(k>j){
dp[i][j][0]=max(dp[i][j][0],dp[i-1][k][1]+pre[i][k]-pre[i][j]);
dp[i][j][0]=max(dp[i][j][0],dp[i-1][k][0]+pre[i][k]-pre[i][j]);
}else if (j==0){
dp[i][j][0]=max({dp[i][j][0],dp[i-1][j][0],dp[i-1][j][1]});
dp[i][j][1]=max({dp[i][j][1],dp[i-1][j][0],dp[i-1][j][1]});
}/*else{
dp[i][j][0]=max({dp[i][j][0],dp[i-1][j][0],dp[i-1][j][1]});
dp[i][j][1]=max(dp[i][j][1],dp[i-1][j][1]);
}*/
ans=max({ans,dp[i][j][0],dp[i][j][1]});
}
}
}
return ans;
}
