#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000001
#define Inf64 1000000000000000001

long long op(long long a,long long b){
	return max(a,b);
}

long long e(){
	return -Inf64;
}

vector<array<long long,4>> v;
vector<long long> dp;

void dfs(int l,int r){
	if(r-l<=1)return;
	int m = (l+r)/2;
	dfs(l,m);
	
	vector<long long> t0,t1;
	for(int i=l;i<r;i++){
		t0.push_back(v[i][1]);
		t1.push_back(v[i][2]);
	}
	sort(t0.begin(),t0.end());
	sort(t1.begin(),t1.end());
	
	vector<vector<int>> qs(t0.size());
	for(int i=l;i<r;i++){
		int d = distance(t0.begin(),lower_bound(t0.begin(),t0.end(),v[i][1]));
		qs[d].push_back(i);
	}
	
	segtree<long long,op,e> seg(t1.size());
	rep(i,t0.size()){
		rep(j,qs[i].size()){
			int ii = qs[i][j];
			int d = distance(t1.begin(),lower_bound(t1.begin(),t1.end(),v[ii][2]));
			if(ii<m){
				seg.set(d,max(seg.get(d),dp[ii]));
			}
			else{
				if(seg.prod(0,d+1)!=-Inf64){
					dp[ii] = max(dp[ii],seg.prod(0,d+1) + v[ii][3]);
				}
			}
		}
	}
	
	
	dfs(m,r);
}

int main() {
	
	int n;
	long long tK;
	cin>>n>>tK;
	vector<long long> t(n),x(n),y(n),a(n);
	{
		vector<long long> T(n),X(n),C(n);
		rep(i,n)cin>>T[i];
		rep(i,n)cin>>X[i];
		rep(i,n)cin>>C[i];
		rep(i,n){
			t[i] = T[i] * tK;
			x[i] = X[i] + 1000000005;
			a[i] = C[i];
			y[i] = 0;
		}
	}
	rep(i,n){
		array<long long,4> A = {y[i],t[i]-y[i]+x[i],t[i]-y[i]-x[i],a[i]};
		v.push_back(A);
	}
	array<long long,4> A = {0,0,0,0};
	v.push_back(A);
	sort(v.begin(),v.end());
	n++;
	dp.assign(n,-Inf64);
	dp[0] = 0;
	dfs(0,n);
	
	long long ans = -Inf64;
	rep(i,n)ans = max(ans,dp[i]);
	
	cout<<ans<<endl;
	
    return 0;
}