#include <bits/stdc++.h>
using namespace std;
typedef long double ld;

int n;

ld R, A, B;

const ld EPS = 1e-9;

int main(){
    ios_base::sync_with_stdio(0);cin.tie(0);

    cin >> n >> R >> A >> B;

    ld a = B;
    ld b = -A;
    vector <pair<ld, int> > vec;

    for (int i = 1; i <= n; i++){
        ld x, y;
        cin >> x >> y;
        ld d1 = fabsl(a*x+b*y)/sqrtl(a*a+b*b);
        if (d1 > R)
            continue;
        ld d2 = sqrtl(x*x+y*y);
        ld len = sqrtl(d2*d2-d1*d1);
        ld drad = sqrtl(R*R-d1*d1);
        if ((x < 0 && b != 0) || (b == 0 && y < 0) )
            len *= -1;
        ld tl = len-drad;
        ld tr = len+drad;
        vec.push_back({tl-EPS, -1});
        vec.push_back({tr+EPS, 1});

    }
    int sum = 0;
    int ans = 0;
    sort(vec.begin(), vec.end());
    for (int i = 0; i < vec.size(); i++){
        sum -= vec[i].second;
        ans = max(ans, sum);
    }
    cout << ans;


}