#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

const long long INF = 3LL << 59;

class segment_tree {
private:
	int size;
	vector<long long> v;
public:
	segment_tree() : size(0), v() {}
	segment_tree(int n) : size(1 << (n >= 2 ? 32 - __builtin_clz(n - 1) : 0)), v(vector<long long>(size * 2, -INF)) {}
	void update(int pos, long long x) {
		pos += size;
		v[pos] = x;
		while (pos > 1) {
			pos /= 2;
			v[pos] = max(v[pos * 2 + 0], v[pos * 2 + 1]);
		}
	}
	long long range_max(int l, int r) {
		l += size;
		r += size;
		long long z = -INF;
		while (l != r) {
			if (l & 1) z = max(z, v[l++]);
			if (r & 1) z = max(z, v[--r]);
			l /= 2;
			r /= 2;
		}
		return z;
	}
};

struct point {
	long long x, y, c;
	bool operator<(const point& p) const {
		return x != p.x ? x < p.x : y < p.y;
	}
};

int main() {
	// step #1. input
	cin.tie(nullptr);
	ios::sync_with_stdio(false);
	int N; long long K;
	cin >> N >> K;
	vector<long long> T(N), X(N), C(N);
	for (int i = 0; i < N; i++) {
		cin >> T[i];
	}
	for (int i = 0; i < N; i++) {
		cin >> X[i];
	}
	for (int i = 0; i < N; i++) {
		cin >> C[i];
	}

	// step #2. preparation
	vector<point> P;
	vector<long long> SY = { 0 };
	for (int i = 0; i < N; i++) {
		long long x = T[i] * K - X[i];
		long long y = T[i] * K + X[i];
		if (x >= 0 && y >= 0) {
			P.push_back(point{x, y, C[i]});
			SY.push_back(y);
		}
	}
	sort(P.begin(), P.end());
	sort(SY.begin(), SY.end());
	SY.erase(unique(SY.begin(), SY.end()), SY.end());
	int M = P.size();
	int Z = SY.size();

	// step #3. dynamic programming
	segment_tree seg(Z);
	seg.update(0, 0);
	for (point p : P) {
		int pos = lower_bound(SY.begin(), SY.end(), p.y) - SY.begin();
		long long x = seg.range_max(0, pos + 1);
		if (x != INF) {
			seg.update(pos, x + p.c);
		}
	}

	// step #4. get answer & output
	long long ans = seg.range_max(0, Z);
	cout << ans << endl;

	return 0;
}