#include<bits/stdc++.h>
using namespace std;
const double pi=acos(-1.0);
struct point{
    double x,y,rd;
    void in(){scanf("%lf %lf",&x,&y);}
    void out(){printf("%lf %lf\n",x,y);}
    point(double xx=0,double yy=0){x=xx,y=yy;}
    point operator + (const point& a)const{return point(x+a.x,y+a.y);}
    point operator - (const point& a)const{return point(x-a.x,y-a.y);}
    double operator *(const point& a)const{return x*a.x+y*a.y;}
    double operator ^(const point& a)const{return x*a.y-y*a.x;}
    bool operator < (const point& a)const{return rd<a.rd;}
};
double len(const point& a){return sqrt(a*a);}
double rad(const point& a){return atan2(a.y,a.x);}
const int maxn=105;
point p[maxn];
double cal(double t,double l,double r)
{
    double w=(r-l);
    if(w<0) w+=2*pi;
    double ans=(int)(t/(2*pi))*w;
    t-=(int)(t/(2*pi))*2.0*pi;
    if(l<r)
    {
        return ans+max(0.0,min(t,r)-l);
    }
    else
    {
        return ans+max(t-l,0.0)+min(t,r);
    }
}
typedef double ld;
ld f1(ld x) {
    if(x<0)x+=pi+pi;
    return x;
}
ld f2(ld x) {
    if(x>pi+pi)x-=pi+pi;
    return x;
}
int main()
{
    //printf("%lf",asin(1/sqrt(5)));
    int n;point s;double d,t;
    scanf("%d",&n);s.in();scanf("%lf %lf",&d,&t);
    for(int i=1;i<=n;i++) p[i].in();
    for(int i=1;i<=n;i++) p[i].rd=rad(p[i]);
    sort(p+1,p+1+n);
    double l,r;
    if(p[n].rd-p[1].rd<pi){
        double dl=asin(d/len(p[1]));
        double dr=asin(d/len(p[n]));
        l=p[1].rd-dl;
        r=p[n].rd+dr;
        for(int i=1;i<=n;i++){
            double di=asin(d/len(p[i]));
            l=min(l,p[i].rd-di);
            r=max(r,p[i].rd+di);
        }
    }
    else
    {
        int pos1=n,pos2=1;
        while(p[pos1].rd-p[pos1-1].rd<pi) pos1--;
        pos2=pos1-1;
        double dl=asin(d/len(p[pos1]));
        double dr=asin(d/len(p[pos2]));
        l=p[pos1].rd-dl;
        r=p[pos2].rd+dr;
        for(int i=n;i>=1;i--) l=min(l,f1(p[i].rd-asin(d/len(p[i]))));
        for(int i=1;i<=n;i++) r=max(r,f2(p[i].rd+asin(d/len(p[i]))));
    }
    if(l>=2*pi) l-=2*pi;
    if(r>=2*pi) r-=2*pi;
    if(l<0) l+=2*pi;
    if(r<0) r+=2*pi;
    printf("%.15lf\n",cal(rad(s)+t,l,r)-cal(rad(s),l,r));
    return 0;
}