#include <bits/stdc++.h>
using namespace std;
#define all(a) begin(a),end(a)
#define sz(a) int(size(a))
#define rep(i,a,b) for(int i=(a);i<(b);++i)
using vi = vector<int>;
using ll = long long;
using pll = pair<ll,ll>;

int n;
ll v;
using Point = pair<ll, ll>;
vector<Point> arr;

int Y;

struct SegTree{
    int n;
    vector<ll> maxx;
    SegTree(int n): n(n), maxx(n * 4 + 1) {}
    void put(int idx, int val, int li=0, int ri=-1, int i=1){
        if(ri == -1) ri = n - 1;

        if(li == ri){
            maxx[i] = val;
            return;
        }

        int mi = (li + ri) / 2;
        if(idx <= mi) put(idx, val, li, mi, 2*i);
        else put(idx, val, mi + 1, ri, 2*i+1);

        // pull
        maxx[i] = max(maxx[2*i], maxx[2*i+1]);
    }
    ll getMax(int s, int e, int li=0, int ri=-1, int i=1){
        if(ri == -1) ri = n - 1;

        if(s <= li && ri <= e) return maxx[i];

        int mi = (li + ri) / 2;
        ll out = 0;
        if(s <= mi) out = max(out, getMax(s, e, li, mi, 2*i));
        if(e > mi) out = max(out, getMax(s, e, mi + 1, ri, 2*i+1));

        return out;
    }
};

void solve(){
    cin >> n >> v;

    // include us at (0, 0)
    ++n;
    arr = vector<Point>(n);
    // times
    for(int i = 1; i < n; ++i){
        ll t;
        cin >> t;
        arr[i].first = t;
    }
    // positions
    for(int i = 1; i < n; ++i){
        ll a;
        cin >> a;
        arr[i].second = a;
    }

    // do the racing gems transform!
    vector<ll> ys;
    for(int i = 0; i < n; ++i){
        auto [x, y] = arr[i];
        // make everything 45 degrees
        x *= v;
        // do 45 rotation
        ll newX = x - y;
        ll newY = x + y;
        // slot em back in
        arr[i] = {newX, newY};

        ys.push_back(newY);
    }

    // coord comp these ys boi
    sort(all(ys));
    ys.erase(unique(all(ys)), end(ys));
    Y = sz(ys);
    for(int i = 0; i < n; ++i){
        auto [x, y] = arr[i];
        y = lower_bound(all(ys), y) - begin(ys);
        arr[i] = {x, y};
    }
    
    Point startPoint = arr[0];

    // LIS...
    sort(all(arr));
    SegTree st(Y);
    for(int i = n - 1; i >= 0; --i){
        auto [x, y] = arr[i];

        ll get = st.getMax(y, Y - 1);

        if(arr[i] == startPoint){
            cout << get << "\n";
            return;
        }

        st.put(y, 1 + get);
    }

    assert(false);
}

int main(){
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.failbit);

    // int t; cin >> t; while(t--)
    solve();

    return 0;
}