#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;
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]);
    ld v=rad(s);
    sort(p+1,p+1+n);
    double l=pi+pi,r=0;
    for(int i=1;i<=n;i++)l=min(l,p[i].rd),r=max(r,p[i].rd);
    while(p[n].rd-p[1].rd>=pi){
        ld d=pi+pi-p[n].rd;
        for(int i=1;i<=n;i++)p[i].rd+=d;
        v+=d;
        for(int i=1;i<=n;i++)if(p[i].rd+(1e-9)>pi+pi)p[i].rd=0;
        sort(p+1,p+1+n);
    }
    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);
    }
    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(v+t,l,r)-cal(v,l,r));
}