#include <iostream>
#include <string>
#include <cstdio>
#include <cstdlib>
#include <set>
#include <map>
#include <vector>
#include <algorithm>
#include <cmath>

using namespace std;
typedef long long LL;

double x0[300008];
double y00[300008];

vector< pair< pair<double, double>, int> > v;

double eps = 1e-9;

int main() {
	int n;
	double r,a,b;
	scanf("%d %lf %lf %lf", &n, &r, &a, &b);
	
	for (int i = 0; i < n; i++){
		scanf("%lf %lf", &x0[i], &y00[i]);
		if (a==0) {
			double rhs = r*r - x0[i]*x0[i];
			if (rhs >= 0) {
				v.push_back(make_pair( make_pair( 0., y00[i] - sqrt(rhs) - eps ), 0 ));
				v.push_back(make_pair( make_pair( 0., y00[i] + sqrt(rhs) ), 1 ));
			}
		}
		else {
			double A = 1;
			double B = -2*x0[i] -2*(b/a)*y00[i];
			double C = x0[i]*x0[i] + y00[i]*y00[i] - r*r;
			double D = B*B - 4*A*C;
			if (D >= 0) {
				v.push_back(make_pair( make_pair( (-B-sqrt(D))/2/A - eps , (b/a)*((-B-sqrt(D))/2/A) ), 0 ));
				v.push_back(make_pair( make_pair( (-B+sqrt(D))/2/A , (b/a)*((-B+sqrt(D))/2/A) ), 1 ));
			}
		}
	}
	
	sort(v.begin(), v.end());

	int ans = 0;
	int mxans = 0;
	
	for (auto& pt : v) {
		if (pt.second == 0) {
			ans++;
		}
		else {
			ans--;
		}
		mxans = max(mxans, ans);
	}
	printf("%d\n", mxans);
	
	return 0;
}