#include "fish.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
set<int>fishies[3002];
ll FIS2;
ll dp[3010][2][3010],fishiess[3010][3010];
inline ll ones(int col,int len){
return fishiess[col][len];
}
ll max_weights(int N,int M,vector<int> X,vector<int> Y,vector<int> W) {
for(int i=0;i<M;i++)
fishies[X[i]+1].insert(Y[i]+1),
fishiess[X[i]+1][Y[i]+1]=W[i];
for(int i=1;i<=N;i++)
for(int j=1;j<=N+1;j++)
fishiess[i][j]+=fishiess[i][j-1];
for(int i=1;i<=N;i++)
fishies[i].insert(1),
fishies[i].insert(N+1);
fishies[N+1].insert(0);
for(auto i:fishies[1])
dp[1][1][i-1]=ones(2,i-1);
for(int i=2;i<=N;i++){
for(auto rw:fishies[i]) {
ll K=0;
for(auto rw2: fishies[i-2]) { rw2--;
K=max(K,max(dp[i-2][0][rw2],dp[i-2][1][rw2])+
ones(i+1,rw-1)+max(0ll,ones(i-1,rw-1)-ones(i-1,rw2)));
}
dp[i][1][rw-1]=K;
}
for(auto rw:fishies[i-1]) { rw--;
for(auto rw2:fishies[i]){
if(rw2-1>rw) break;
ll K=ones(i+1,rw2-1)-ones(i,rw2-1)+dp[i-1][0][rw];
dp[i][0][rw2-1]=max(dp[i][0][rw2-1],K);
}
}
for(auto rw:fishies[i-1]){rw--;
for(auto rw2:fishies[i]){
ll K=ones(i+1,rw2-1)-ones(i,min(rw,rw2-1))+
ones(i-1,rw2-1)-ones(i-1,min(rw2-1,rw))+dp[i-1][1][rw];
dp[i][rw2>rw][rw2-1]=max(dp[i][rw2>rw][rw2-1],K);
}
}
}
ll ans=0;
for(int i=0;i<=N;i++)
ans=max({ans,dp[N][0][i],dp[N][1][i]});
return ans;
}
