#include<bits/stdc++.h>
using namespace std;
#define foru(i,a,b) for(int i=(a); i<=(b); ++i)
#define ford(i,a,b) for(int i=(a); i>=(b); --i)
#define rep(i,a) for(int i=0; i<(a); ++i)
#define sz(a) (int)(a).size()
#define all(a) (a).begin(),(a).end()
#define bit(s,i) (((s)>>(i))&1)
#define ii pair<int,int>
#define fi first
#define se second
#define pb push_back
#define eb emplace_back
#define ll long long
#define _ << " " <<
template <class X, class Y> bool maxi(X &x, Y y){return x<y?x=y,true:false;}
template <class X, class Y> bool mini(X &x, Y y){return x>y?x=y,true:false;}
const int MAX = 333;
ll dp[MAX][MAX][2],sum[MAX][MAX],mxDP[MAX];
ll max_weights(int N, int M, vector<int> X, vector<int> Y, vector<int> W){
assert(N<=300);
rep(i,M) sum[++X[i]][++Y[i]]=W[i];
foru(i,1,N) foru(j,1,N) sum[i][j]+=sum[i][j-1];
foru(j,0,N) dp[0][j][0]=dp[0][j][1]=-1e18;
dp[0][0][0]=0;
foru(i,1,N) foru(j,0,N){
foru(k,0,j-1){
maxi(dp[i][j][0], max(dp[i-1][k][0] + (sum[i-1][j]-sum[i-1][k]), dp[i-1][k][1]));
if(i>=2) maxi(dp[i][j][0], mxDP[i-2] + sum[i-1][j]);
}
foru(k,j,N){
maxi(dp[i][j][1], max(dp[i-1][k][0], dp[i-1][k][1]) + (sum[i][k]-sum[i][j]));
}
maxi(mxDP[i], max(dp[i][j][0],dp[i][j][1]));
// if(dp[i][j][0]==10)cout<<i _ j _ 0<<'\n';
// if(dp[i][j][1]==10)cout<<i _ j _ 1<<'\n';
}
return mxDP[N];
}
