// #pragma GCC target("avx2")
// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")
// #define INTERACTIVE

#include <bits/stdc++.h>
using namespace std;

namespace templates {
// type
using ll  = long long;
using ull = unsigned long long;
using Pii = pair<int, int>;
using Pil = pair<int, ll>;
using Pli = pair<ll, int>;
using Pll = pair<ll, ll>;
template <class T>
using pq = priority_queue<T>;
template <class T>
using qp = priority_queue<T, vector<T>, greater<T>>;
// clang-format off
#define vec(T, A, ...) vector<T> A(__VA_ARGS__);
#define vvec(T, A, h, ...) vector<vector<T>> A(h, vector<T>(__VA_ARGS__));
#define vvvec(T, A, h1, h2, ...) vector<vector<vector<T>>> A(h1, vector<vector<T>>(h2, vector<T>(__VA_ARGS__)));
// clang-format on

// for loop
#define fori1(a) for (ll _ = 0; _ < (a); _++)
#define fori2(i, a) for (ll i = 0; i < (a); i++)
#define fori3(i, a, b) for (ll i = (a); i < (b); i++)
#define fori4(i, a, b, c) for (ll i = (a); ((c) > 0 || i > (b)) && ((c) < 0 || i < (b)); i += (c))
#define overload4(a, b, c, d, e, ...) e
#define fori(...) overload4(__VA_ARGS__, fori4, fori3, fori2, fori1)(__VA_ARGS__)

// declare and input
// clang-format off
#define INT(...) int __VA_ARGS__; inp(__VA_ARGS__);
#define LL(...) ll __VA_ARGS__; inp(__VA_ARGS__);
#define STRING(...) string __VA_ARGS__; inp(__VA_ARGS__);
#define CHAR(...) char __VA_ARGS__; inp(__VA_ARGS__);
#define DOUBLE(...) double __VA_ARGS__; STRING(str___); __VA_ARGS__ = stod(str___);
#define VEC(T, A, n) vector<T> A(n); inp(A);
#define VVEC(T, A, n, m) vector<vector<T>> A(n, vector<T>(m)); inp(A);
// clang-format on

// const value
const ll MOD1   = 1000000007;
const ll MOD9   = 998244353;
const double PI = acos(-1);

// other macro
#if !defined(RIN__LOCAL) && !defined(INTERACTIVE)
#define endl "\n"
#endif
#define spa ' '
#define len(A) ll(A.size())
#define all(A) begin(A), end(A)

// function
vector<char> stoc(string &S) {
    int n = S.size();
    vector<char> ret(n);
    for (int i = 0; i < n; i++) ret[i] = S[i];
    return ret;
}
string ctos(vector<char> &S) {
    int n      = S.size();
    string ret = "";
    for (int i = 0; i < n; i++) ret += S[i];
    return ret;
}

template <class T>
auto min(const T &a) {
    return *min_element(all(a));
}
template <class T>
auto max(const T &a) {
    return *max_element(all(a));
}
template <class T, class S>
auto clamp(T &a, const S &l, const S &r) {
    return (a > r ? r : a < l ? l : a);
}
template <class T, class S>
inline bool chmax(T &a, const S &b) {
    return (a < b ? a = b, 1 : 0);
}
template <class T, class S>
inline bool chmin(T &a, const S &b) {
    return (a > b ? a = b, 1 : 0);
}
template <class T, class S>
inline bool chclamp(T &a, const S &l, const S &r) {
    auto b = clamp(a, l, r);
    return (a != b ? a = b, 1 : 0);
}

template <typename T>
T sum(vector<T> &A) {
    T tot = 0;
    for (auto a : A) tot += a;
    return tot;
}

template <typename T>
vector<T> compression(vector<T> X) {
    sort(all(X));
    X.erase(unique(all(X)), X.end());
    return X;
}

// input and output
namespace io {
// __int128_t
std::ostream &operator<<(std::ostream &dest, __int128_t value) {
    std::ostream::sentry s(dest);
    if (s) {
        __uint128_t tmp = value < 0 ? -value : value;
        char buffer[128];
        char *d = std::end(buffer);
        do {
            --d;
            *d = "0123456789"[tmp % 10];
            tmp /= 10;
        } while (tmp != 0);
        if (value < 0) {
            --d;
            *d = '-';
        }
        int len = std::end(buffer) - d;
        if (dest.rdbuf()->sputn(d, len) != len) {
            dest.setstate(std::ios_base::badbit);
        }
    }
    return dest;
}

// vector<T>
template <typename T>
istream &operator>>(istream &is, vector<T> &A) {
    for (auto &a : A) is >> a;
    return is;
}
template <typename T>
ostream &operator<<(ostream &os, vector<T> &A) {
    for (size_t i = 0; i < A.size(); i++) {
        os << A[i];
        if (i != A.size() - 1) os << ' ';
    }
    return os;
}

// vector<vector<T>>
template <typename T>
istream &operator>>(istream &is, vector<vector<T>> &A) {
    for (auto &a : A) is >> a;
    return is;
}
template <typename T>
ostream &operator<<(ostream &os, vector<vector<T>> &A) {
    for (size_t i = 0; i < A.size(); i++) {
        os << A[i];
        if (i != A.size() - 1) os << endl;
    }
    return os;
}

// pair<S, T>
template <typename S, typename T>
istream &operator>>(istream &is, pair<S, T> &A) {
    is >> A.first >> A.second;
    return is;
}
template <typename S, typename T>
ostream &operator<<(ostream &os, pair<S, T> &A) {
    os << A.first << ' ' << A.second;
    return os;
}

// vector<pair<S, T>>
template <typename S, typename T>
istream &operator>>(istream &is, vector<pair<S, T>> &A) {
    for (size_t i = 0; i < A.size(); i++) {
        is >> A[i];
    }
    return is;
}
template <typename S, typename T>
ostream &operator<<(ostream &os, vector<pair<S, T>> &A) {
    for (size_t i = 0; i < A.size(); i++) {
        os << A[i];
        if (i != A.size() - 1) os << endl;
    }
    return os;
}

// tuple
template <typename T, size_t N>
struct TuplePrint {
    static ostream &print(ostream &os, const T &t) {
        TuplePrint<T, N - 1>::print(os, t);
        os << ' ' << get<N - 1>(t);
        return os;
    }
};
template <typename T>
struct TuplePrint<T, 1> {
    static ostream &print(ostream &os, const T &t) {
        os << get<0>(t);
        return os;
    }
};
template <typename... Args>
ostream &operator<<(ostream &os, const tuple<Args...> &t) {
    TuplePrint<decltype(t), sizeof...(Args)>::print(os, t);
    return os;
}

// io functions
void FLUSH() {
    cout << flush;
}

void print() {
    cout << endl;
}
template <class Head, class... Tail>
void print(Head &&head, Tail &&...tail) {
    cout << head;
    if (sizeof...(Tail)) cout << spa;
    print(std::forward<Tail>(tail)...);
}

template <typename T, typename S>
void prisep(vector<T> &A, S sep) {
    int n = A.size();
    for (int i = 0; i < n; i++) {
        cout << A[i];
        if (i != n - 1) cout << sep;
    }
    cout << endl;
}
template <typename T, typename S>
void priend(T A, S end) {
    cout << A << end;
}
template <typename T>
void prispa(T A) {
    priend(A, spa);
}
template <typename T, typename S>
bool printif(bool f, T A, S B) {
    if (f)
        print(A);
    else
        print(B);
    return f;
}

template <class... T>
void inp(T &...a) {
    (cin >> ... >> a);
}

} // namespace io
using namespace io;

// read graph
vector<vector<int>> read_edges(int n, int m, bool direct = false, int indexed = 1) {
    vector<vector<int>> edges(n, vector<int>());
    for (int i = 0; i < m; i++) {
        INT(u, v);
        u -= indexed;
        v -= indexed;
        edges[u].push_back(v);
        if (!direct) edges[v].push_back(u);
    }
    return edges;
}
vector<vector<int>> read_tree(int n, int indexed = 1) {
    return read_edges(n, n - 1, false, indexed);
}

template <typename T = long long>
vector<vector<pair<int, T>>> read_wedges(int n, int m, bool direct = false, int indexed = 1) {
    vector<vector<pair<int, T>>> edges(n, vector<pair<int, T>>());
    for (int i = 0; i < m; i++) {
        INT(u, v);
        T w;
        inp(w);
        u -= indexed;
        v -= indexed;
        edges[u].push_back({v, w});
        if (!direct) edges[v].push_back({u, w});
    }
    return edges;
}
template <typename T = long long>
vector<vector<pair<int, T>>> read_wtree(int n, int indexed = 1) {
    return read_wedges<T>(n, n - 1, false, indexed);
}

// yes / no
namespace yesno {

// yes
inline bool yes(bool f = true) {
    cout << (f ? "yes" : "no") << endl;
    return f;
}
inline bool Yes(bool f = true) {
    cout << (f ? "Yes" : "No") << endl;
    return f;
}
inline bool YES(bool f = true) {
    cout << (f ? "YES" : "NO") << endl;
    return f;
}

// no
inline bool no(bool f = true) {
    cout << (!f ? "yes" : "no") << endl;
    return f;
}
inline bool No(bool f = true) {
    cout << (!f ? "Yes" : "No") << endl;
    return f;
}
inline bool NO(bool f = true) {
    cout << (!f ? "YES" : "NO") << endl;
    return f;
}

// possible
inline bool possible(bool f = true) {
    cout << (f ? "possible" : "impossible") << endl;
    return f;
}
inline bool Possible(bool f = true) {
    cout << (f ? "Possible" : "Impossible") << endl;
    return f;
}
inline bool POSSIBLE(bool f = true) {
    cout << (f ? "POSSIBLE" : "IMPOSSIBLE") << endl;
    return f;
}

// impossible
inline bool impossible(bool f = true) {
    cout << (!f ? "possible" : "impossible") << endl;
    return f;
}
inline bool Impossible(bool f = true) {
    cout << (!f ? "Possible" : "Impossible") << endl;
    return f;
}
inline bool IMPOSSIBLE(bool f = true) {
    cout << (!f ? "POSSIBLE" : "IMPOSSIBLE") << endl;
    return f;
}

// Alice Bob
inline bool Alice(bool f = true) {
    cout << (f ? "Alice" : "Bob") << endl;
    return f;
}
inline bool Bob(bool f = true) {
    cout << (f ? "Bob" : "Alice") << endl;
    return f;
}

// Takahashi Aoki
inline bool Takahashi(bool f = true) {
    cout << (f ? "Takahashi" : "Aoki") << endl;
    return f;
}
inline bool Aoki(bool f = true) {
    cout << (f ? "Aoki" : "Takahashi") << endl;
    return f;
}

} // namespace yesno
using namespace yesno;

} // namespace templates
using namespace templates;

// #include "data_structure/segTree.hpp"

/////// https://hitonanode.github.io/cplib-cpp/segmenttree/rangetree.hpp.html
#ifndef ATCODER_SEGTREE_HPP
#define ATCODER_SEGTREE_HPP 1

#include <algorithm>
#include <cassert>
#include <vector>

#ifndef ATCODER_INTERNAL_BITOP_HPP
#define ATCODER_INTERNAL_BITOP_HPP 1

#ifdef _MSC_VER
#include <intrin.h>
#endif

namespace atcoder {

namespace internal {

// @param n `0 <= n`
// @return minimum non-negative `x` s.t. `n <= 2**x`
int ceil_pow2(int n) {
    int x = 0;
    while ((1U << x) < (unsigned int)(n)) x++;
    return x;
}

// @param n `1 <= n`
// @return minimum non-negative `x` s.t. `(n & (1 << x)) != 0`
constexpr int bsf_constexpr(unsigned int n) {
    int x = 0;
    while (!(n & (1 << x))) x++;
    return x;
}

// @param n `1 <= n`
// @return minimum non-negative `x` s.t. `(n & (1 << x)) != 0`
int bsf(unsigned int n) {
#ifdef _MSC_VER
    unsigned long index;
    _BitScanForward(&index, n);
    return index;
#else
    return __builtin_ctz(n);
#endif
}

} // namespace internal

} // namespace atcoder

#endif // ATCODER_INTERNAL_BITOP_HPP

namespace atcoder {

template <class S, S (*op)(S, S), S (*e)()>
struct segtree {
  public:
    segtree() : segtree(0) {}
    explicit segtree(int n) : segtree(std::vector<S>(n, e())) {}
    explicit segtree(const std::vector<S> &v) : _n(int(v.size())) {
        log  = internal::ceil_pow2(_n);
        size = 1 << log;
        d    = std::vector<S>(2 * size, e());
        for (int i = 0; i < _n; i++) d[size + i] = v[i];
        for (int i = size - 1; i >= 1; i--) {
            update(i);
        }
    }

    void set(int p, S x) {
        assert(0 <= p && p < _n);
        p += size;
        d[p] = x;
        for (int i = 1; i <= log; i++) update(p >> i);
    }

    S get(int p) const {
        assert(0 <= p && p < _n);
        return d[p + size];
    }

    S prod(int l, int r) const {
        assert(0 <= l && l <= r && r <= _n);
        S sml = e(), smr = e();
        l += size;
        r += size;

        while (l < r) {
            if (l & 1) sml = op(sml, d[l++]);
            if (r & 1) smr = op(d[--r], smr);
            l >>= 1;
            r >>= 1;
        }
        return op(sml, smr);
    }

    S all_prod() const {
        return d[1];
    }

    template <bool (*f)(S)>
    int max_right(int l) const {
        return max_right(l, [](S x) { return f(x); });
    }
    template <class F>
    int max_right(int l, F f) const {
        assert(0 <= l && l <= _n);
        assert(f(e()));
        if (l == _n) return _n;
        l += size;
        S sm = e();
        do {
            while (l % 2 == 0) l >>= 1;
            if (!f(op(sm, d[l]))) {
                while (l < size) {
                    l = (2 * l);
                    if (f(op(sm, d[l]))) {
                        sm = op(sm, d[l]);
                        l++;
                    }
                }
                return l - size;
            }
            sm = op(sm, d[l]);
            l++;
        } while ((l & -l) != l);
        return _n;
    }

    template <bool (*f)(S)>
    int min_left(int r) const {
        return min_left(r, [](S x) { return f(x); });
    }
    template <class F>
    int min_left(int r, F f) const {
        assert(0 <= r && r <= _n);
        assert(f(e()));
        if (r == 0) return 0;
        r += size;
        S sm = e();
        do {
            r--;
            while (r > 1 && (r % 2)) r >>= 1;
            if (!f(op(d[r], sm))) {
                while (r < size) {
                    r = (2 * r + 1);
                    if (f(op(d[r], sm))) {
                        sm = op(d[r], sm);
                        r--;
                    }
                }
                return r + 1 - size;
            }
            sm = op(d[r], sm);
        } while ((r & -r) != r);
        return 0;
    }

  private:
    int _n, size, log;
    std::vector<S> d;

    void update(int k) {
        d[k] = op(d[2 * k], d[2 * k + 1]);
    }
};

} // namespace atcoder

#endif // ATCODER_SEGTREE_HPP

// CUT begin
// 逆元を要求しない領域木
template <class S, S (*op)(S, S), S (*e)(), class Coordinate>
class rangetree {
    int n;
    using Pt = std::pair<Coordinate, Coordinate>;
    std::vector<Pt> _pts;
    std::vector<std::vector<Pt>> _range2yxs;
    std::vector<atcoder::segtree<S, op, e>> segtrees;
    void _set(int v, Pt p, S val) {
        auto i = std::distance(
            _range2yxs[v].begin(),
            std::lower_bound(_range2yxs[v].begin(), _range2yxs[v].end(), Pt{p.second, p.first}));
        segtrees[v].set(i, val);
    }
    void _add(int v, Pt p, S val) {
        auto i = std::distance(
            _range2yxs[v].begin(),
            std::lower_bound(_range2yxs[v].begin(), _range2yxs[v].end(), Pt{p.second, p.first}));
        segtrees[v].set(i, op(segtrees[v].get(i), val));
    }
    S _prod(int v, Coordinate yl, Coordinate yr) const {
        auto comp = [&](const Pt &l, const Pt &r) { return l.first < r.first; };
        auto il   = std::distance(
            _range2yxs[v].begin(),
            std::lower_bound(_range2yxs[v].begin(), _range2yxs[v].end(), Pt{yl, yl}, comp));
        auto ir = std::distance(
            _range2yxs[v].begin(),
            std::lower_bound(_range2yxs[v].begin(), _range2yxs[v].end(), Pt{yr, yr}, comp));
        return segtrees[v].prod(il, ir);
    }

  public:
    rangetree() = default;
    void add_point(Coordinate x, Coordinate y) noexcept {
        _pts.emplace_back(x, y);
    }
    void build() {
        std::sort(_pts.begin(), _pts.end());
        _pts.erase(std::unique(_pts.begin(), _pts.end()), _pts.end());
        n = _pts.size();

        _range2yxs.resize(n * 2);
        for (int i = 0; i < n; i++) _range2yxs[n + i] = {{_pts[i].second, _pts[i].first}};
        for (int i = n - 1; i > 0; i--) {
            auto &lch = _range2yxs[i * 2];
            auto &rch = _range2yxs[i * 2 + 1];
            std::merge(lch.begin(), lch.end(), rch.begin(), rch.end(),
                       std::back_inserter(_range2yxs[i]));
            _range2yxs[i].erase(std::unique(_range2yxs[i].begin(), _range2yxs[i].end()),
                                _range2yxs[i].end());
        }
        for (const auto &v : _range2yxs) segtrees.emplace_back(v.size());
    }
    void set(Coordinate x, Coordinate y, S val) {
        int i = std::distance(_pts.begin(), std::lower_bound(_pts.begin(), _pts.end(), Pt{x, y}));
        assert(i < n and _pts[i] == std::make_pair(x, y));
        for (i += n; i; i >>= 1) _set(i, {x, y}, val);
    }
    void add(Coordinate x, Coordinate y, S val) {
        int i = std::distance(_pts.begin(), std::lower_bound(_pts.begin(), _pts.end(), Pt{x, y}));
        assert(i < n and _pts[i] == std::make_pair(x, y));
        for (i += n; i; i >>= 1) _add(i, {x, y}, val);
    }
    S prod(Coordinate xl, Coordinate xr, Coordinate yl, Coordinate yr) const {
        auto comp = [](const Pt &l, const Pt &r) { return l.first < r.first; };
        int l     = n + std::distance(_pts.begin(),
                                      std::lower_bound(_pts.begin(), _pts.end(), Pt{xl, yr}, comp));
        int r     = n + std::distance(_pts.begin(),
                                      std::lower_bound(_pts.begin(), _pts.end(), Pt{xr, yr}, comp));
        S ret     = e();
        while (l < r) {
            if (l & 1) ret = op(ret, _prod(l++, yl, yr));
            if (r & 1) ret = op(ret, _prod(--r, yl, yr));
            l >>= 1, r >>= 1;
        }
        return ret;
    }
    S get(Coordinate x, Coordinate y) const {
        return prod(x, x + 1, y, y + 1);
    }
};

const ll inf = 1LL << 60;
using S      = ll;
S op(S l, S r) {
    return l > r ? l : r;
}
S e() {
    return -inf;
}

void solve() {
    LL(n, K);
    VEC(ll, T, n);
    VEC(ll, X, n);
    VEC(ll, C, n);
    vec(int, ind, n);
    iota(all(ind), 0);
    sort(all(ind), [&](int i, int j) { return T[i] < T[j]; });

    rangetree<S, op, e, ll> seg_R;
    rangetree<S, op, e, ll> seg_L;
    vec(ll, add, n);
    vec(ll, sub, n);
    add.push_back(0);
    sub.push_back(0);
    fori(i, n) {
        add[i] = X[i] + K * T[i];
        sub[i] = X[i] - K * T[i];
    }
    add     = compression(add);
    sub     = compression(sub);
    auto X2 = X;
    X2.push_back(0);
    X2 = compression(X2);

    fori(i, n) {
        int xp = lower_bound(all(X2), X[i]) - X2.begin();
        int ap = lower_bound(all(add), X[i] + K * T[i]) - add.begin();
        int sp = lower_bound(all(sub), X[i] - K * T[i]) - sub.begin();
        seg_R.add_point(xp, ap);
        seg_L.add_point(xp, sp);
    }

    {
        int xp = lower_bound(all(X2), 0) - X2.begin();
        int ap = lower_bound(all(add), 0) - add.begin();
        int sp = lower_bound(all(sub), 0) - sub.begin();

        seg_R.add_point(xp, ap);
        seg_L.add_point(xp, sp);
        seg_R.build();
        seg_L.build();
        seg_R.set(xp, ap, 0);
        seg_L.set(xp, sp, 0);
    }
    ll ans = 0;
    for (auto i : ind) {
        int xp = lower_bound(all(X2), X[i]) - X2.begin();
        int ap = lower_bound(all(add), X[i] + K * T[i]) - add.begin();
        int sp = lower_bound(all(sub), X[i] - K * T[i]) - sub.begin();
        ll r   = seg_R.prod(xp, len(X2), 0, ap);
        ll l   = seg_L.prod(0, xp, sp, len(sub));
        ll ma  = max(r, l) + C[i];
        chmax(ans, ma);
        seg_R.set(xp, ap, ma);
        seg_L.set(xp, sp, ma);
    }
    print(ans);
}

int main() {
#ifndef INTERACTIVE
    std::cin.tie(0)->sync_with_stdio(0);
#endif
    // std::cout << std::fixed << std::setprecision(12);
    int t;
    t = 1;
    // std::cin >> t;
    while (t--) solve();
    return 0;
}

// // #pragma GCC target("avx2")
// // #pragma GCC optimize("O3")
// // #pragma GCC optimize("unroll-loops")
// // #define INTERACTIVE
//
// #include "kyopro-cpp/template.hpp"
//
// // #include "data_structure/segTree.hpp"
//
// /////// https://hitonanode.github.io/cplib-cpp/segmenttree/rangetree.hpp.html
// #include "atcoder/segtree.hpp"
//
// // CUT begin
// // 逆元を要求しない領域木
// template <class S, S (*op)(S, S), S (*e)(), class Coordinate>
// class rangetree {
//     int n;
//     using Pt = std::pair<Coordinate, Coordinate>;
//     std::vector<Pt> _pts;
//     std::vector<std::vector<Pt>> _range2yxs;
//     std::vector<atcoder::segtree<S, op, e>> segtrees;
//     void _set(int v, Pt p, S val) {
//         auto i = std::distance(
//             _range2yxs[v].begin(),
//             std::lower_bound(_range2yxs[v].begin(), _range2yxs[v].end(), Pt{p.second, p.first}));
//         segtrees[v].set(i, val);
//     }
//     void _add(int v, Pt p, S val) {
//         auto i = std::distance(
//             _range2yxs[v].begin(),
//             std::lower_bound(_range2yxs[v].begin(), _range2yxs[v].end(), Pt{p.second, p.first}));
//         segtrees[v].set(i, op(segtrees[v].get(i), val));
//     }
//     S _prod(int v, Coordinate yl, Coordinate yr) const {
//         auto comp = [&](const Pt &l, const Pt &r) { return l.first < r.first; };
//         auto il   = std::distance(
//             _range2yxs[v].begin(),
//             std::lower_bound(_range2yxs[v].begin(), _range2yxs[v].end(), Pt{yl, yl}, comp));
//         auto ir = std::distance(
//             _range2yxs[v].begin(),
//             std::lower_bound(_range2yxs[v].begin(), _range2yxs[v].end(), Pt{yr, yr}, comp));
//         return segtrees[v].prod(il, ir);
//     }
//
//   public:
//     rangetree() = default;
//     void add_point(Coordinate x, Coordinate y) noexcept {
//         _pts.emplace_back(x, y);
//     }
//     void build() {
//         std::sort(_pts.begin(), _pts.end());
//         _pts.erase(std::unique(_pts.begin(), _pts.end()), _pts.end());
//         n = _pts.size();
//
//         _range2yxs.resize(n * 2);
//         for (int i = 0; i < n; i++) _range2yxs[n + i] = {{_pts[i].second, _pts[i].first}};
//         for (int i = n - 1; i > 0; i--) {
//             auto &lch = _range2yxs[i * 2];
//             auto &rch = _range2yxs[i * 2 + 1];
//             std::merge(lch.begin(), lch.end(), rch.begin(), rch.end(),
//                        std::back_inserter(_range2yxs[i]));
//             _range2yxs[i].erase(std::unique(_range2yxs[i].begin(), _range2yxs[i].end()),
//                                 _range2yxs[i].end());
//         }
//         for (const auto &v : _range2yxs) segtrees.emplace_back(v.size());
//     }
//     void set(Coordinate x, Coordinate y, S val) {
//         int i = std::distance(_pts.begin(), std::lower_bound(_pts.begin(), _pts.end(), Pt{x,
//         y})); assert(i < n and _pts[i] == std::make_pair(x, y)); for (i += n; i; i >>= 1) _set(i,
//         {x, y}, val);
//     }
//     void add(Coordinate x, Coordinate y, S val) {
//         int i = std::distance(_pts.begin(), std::lower_bound(_pts.begin(), _pts.end(), Pt{x,
//         y})); assert(i < n and _pts[i] == std::make_pair(x, y)); for (i += n; i; i >>= 1) _add(i,
//         {x, y}, val);
//     }
//     S prod(Coordinate xl, Coordinate xr, Coordinate yl, Coordinate yr) const {
//         auto comp = [](const Pt &l, const Pt &r) { return l.first < r.first; };
//         int l     = n + std::distance(_pts.begin(),
//                                       std::lower_bound(_pts.begin(), _pts.end(), Pt{xl, yr},
//                                       comp));
//         int r     = n + std::distance(_pts.begin(),
//                                       std::lower_bound(_pts.begin(), _pts.end(), Pt{xr, yr},
//                                       comp));
//         S ret     = e();
//         while (l < r) {
//             if (l & 1) ret = op(ret, _prod(l++, yl, yr));
//             if (r & 1) ret = op(ret, _prod(--r, yl, yr));
//             l >>= 1, r >>= 1;
//         }
//         return ret;
//     }
//     S get(Coordinate x, Coordinate y) const {
//         return prod(x, x + 1, y, y + 1);
//     }
// };
//
// const ll inf = 1LL << 60;
// using S      = ll;
// S op(S l, S r) {
//     return l > r ? l : r;
// }
// S e() {
//     return -inf;
// }
//
// void solve() {
//     LL(n, K);
//     VEC(ll, T, n);
//     VEC(ll, X, n);
//     VEC(ll, C, n);
//     vec(int, ind, n);
//     iota(all(ind), 0);
//     sort(all(ind), [&](int i, int j) { return T[i] < T[j]; });
//
//     rangetree<S, op, e, ll> seg_R;
//     rangetree<S, op, e, ll> seg_L;
//     vec(ll, add, n);
//     vec(ll, sub, n);
//     add.push_back(0);
//     sub.push_back(0);
//     fori(i, n) {
//         add[i] = X[i] + K * T[i];
//         sub[i] = X[i] - K * T[i];
//     }
//     add     = compression(add);
//     sub     = compression(sub);
//     auto X2 = X;
//     X2.push_back(0);
//     X2 = compression(X2);
//
//     fori(i, n) {
//         int xp = lower_bound(all(X2), X[i]) - X2.begin();
//         int ap = lower_bound(all(add), X[i] + K * T[i]) - add.begin();
//         int sp = lower_bound(all(sub), X[i] - K * T[i]) - sub.begin();
//         seg_R.add_point(xp, ap);
//         seg_L.add_point(xp, sp);
//     }
//
//     {
//         int xp = lower_bound(all(X2), 0) - X2.begin();
//         int ap = lower_bound(all(add), 0) - add.begin();
//         int sp = lower_bound(all(sub), 0) - sub.begin();
//
//         seg_R.add_point(xp, ap);
//         seg_L.add_point(xp, sp);
//         seg_R.build();
//         seg_L.build();
//         seg_R.set(xp, ap, 0);
//         seg_L.set(xp, sp, 0);
//     }
//     ll ans = 0;
//     for (auto i : ind) {
//         int xp = lower_bound(all(X2), X[i]) - X2.begin();
//         int ap = lower_bound(all(add), X[i] + K * T[i]) - add.begin();
//         int sp = lower_bound(all(sub), X[i] - K * T[i]) - sub.begin();
//         ll r   = seg_R.prod(xp, len(X2), 0, ap);
//         ll l   = seg_L.prod(0, xp, sp, len(sub));
//         ll ma  = max(r, l) + C[i];
//         chmax(ans, ma);
//         seg_R.set(xp, ap, ma);
//         seg_L.set(xp, sp, ma);
//     }
//     print(ans);
// }
//
// int main() {
// #ifndef INTERACTIVE
//     std::cin.tie(0)->sync_with_stdio(0);
// #endif
//     // std::cout << std::fixed << std::setprecision(12);
//     int t;
//     t = 1;
//     // std::cin >> t;
//     while (t--) solve();
//     return 0;
// }