#include <bits/stdc++.h>
#define pb push_back
#define fst first
#define snd second
#define fore(i,a,b) for(int i=a,pao=b;i<pao;++i)
#define SZ(x) ((int)x.size())
#define ALL(x) x.begin(),x.end()
#define mset(a,v) memset((a),(v),sizeof(a))
#define FIN ios::sync_with_stdio(0);cin.tie(0);cout.tie(0)
using namespace std;
typedef long long ll;
const int MAXN=305;
const ll INF=1e18;
ll pref[MAXN][MAXN],dp[MAXN][MAXN][2];
long long max_weights(int N, int M, std::vector<int> X, std::vector<int> Y, std::vector<int> W) {
fore(i,0,M){
pref[X[i]+1][Y[i]+1]+=W[i];
}
fore(i,0,N+1){
fore(j,1,N+1){
pref[i][j]+=pref[i][j-1];
}
}
fore(i,0,N+1)fore(j,0,N+1)fore(k,0,2)dp[i][j][k]=-INF;
ll ans=0;
dp[0][0][1]=0;
fore(i,1,N+1){
fore(x,0,N+1){
fore(y,0,N+1){
if(y==0){
ll &dpv=dp[i][y][1];
dpv=max(dpv,dp[i-1][x][0]);
dpv=max(dpv,dp[i-1][x][1]);
ll &dpv2=dp[i][y][0];
dpv2=max(dpv2,dp[i-1][x][0]);
dpv2=max(dpv2,dp[i-1][x][1]);
}
if(x<=y){
ll &dpv=dp[i][y][1];
dpv=max(dpv,dp[i-1][x][1]+(pref[i-1][y]-pref[i-1][x]));
}
if(x>=y){
ll &dpv=dp[i][y][0];
dpv=max(dpv,dp[i-1][x][0]+(pref[i][x]-pref[i][y]));
dpv=max(dpv,dp[i-1][x][1]+(pref[i][x]-pref[i][y]));
}
ans=max(ans,dp[i][y][0]);
ans=max(ans,dp[i][y][1]);
}
}
}
return ans;
}
