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

#ifdef DEB
#define D if(1)
#else 
#define D if(0)
#endif

const int NMAX = 512345;

struct Bod
{
	ld x,y;
	void rot(ld sina,ld cosa)
	{
		ld oldx=x;
		ld oldy=y;
		x = - sina*oldy + cosa*oldx;
		y =   sina*oldx + cosa*oldy;
	}
};
int n;
ld r;
Bod zaklad;
Bod arr[NMAX];

pair<ld,int> sour [2*NMAX];
int soulen=0;
int main()
{
	scanf("%d%LF%LF%LF",&n,&r,&(zaklad.x),&(zaklad.y));
	int invertx = (zaklad.x<0)?-1:1;
	int inverty = (zaklad.y<0)?-1:1;
	zaklad.x *= invertx;
	zaklad.y *= inverty;
	r += 0.0001;
	ld uhel;
	if(zaklad.x==0)
	{
		uhel = ld(M_PI)/2;
	}
	else
	{
		uhel = - atan(zaklad.y/zaklad.x);
	}
	ld sina = sin(uhel);
	ld cosa = cos(uhel);
	D printf("x=%d\ny=%d\n",invertx,inverty);
	D printf("s=%LF\nc=%LF\n",sina,cosa);
	for(int i=0;i<n;i++)
	{
		scanf("%LF%LF",&(arr[i].x),&(arr[i].y));
		arr[i].x *= invertx;
		arr[i].y *= inverty;
		arr[i].rot(sina,cosa);
	}
	D for(int i=0;i<n;i++)
	{
		printf("%LF %LF\n",arr[i].x,arr[i].y);
	}
	for(int i=0;i<n;i++)
	{
		if(r*r-arr[i].y*arr[i].y>=0)
		{
			ld dis = sqrt(r*r-arr[i].y*arr[i].y);
			sour[soulen++]={arr[i].x-dis,1};
			sour[soulen++]={arr[i].x+dis,-1};
		}
	}
	sort(sour,sour+soulen);
	int p=0;
	int out = 0;
	for(int i=0;i<soulen;i++)
	{
		p+=sour[i].second;
		out=max(out,p);
	}
	printf("%d\n",out);
	return 0;
}