#include<bits/stdc++.h>
using namespace std;

using ll=long long;
#define endl '\n'
#define pi 3.141592653589793238462643383279502884

struct point{
    long double x,y;
}p[101],C;
struct vec{
    long double x,y;
    long double length()
    {
        return sqrt(x*x+y*y);
    }
};
long double dot(vec a,vec b)
{
    return a.x*b.x+a.y*b.y;
}
long double cross(vec a,vec b)
{
    return a.x*b.y-a.y*b.x;
}
vec pointvec(point A,point B)
{
    vec a;
    a.x=B.x-A.x;
    a.y=B.y-A.y;
    return a;
}

ll n;
long double d,t,tmax,tmin,ans,k,tmid,deg,res[201];

void solve(point cur,int id)
{
    vec a,b;
    a=pointvec(C,p[0]);
    b=pointvec(C,cur);
    
    deg=asin(d/b.length());
    tmid=asin(cross(a,b)/(a.length()*b.length()));
    
    if(dot(a,b)<=0)
    {
        if(cross(a,b)>0&&dot(a,b)<0)
        {
            tmid=pi-tmid;
        }
        if(cross(a,b)<0&&dot(a,b)<=0)
        {
            tmid=-pi-tmid;
        }
    }
    if(cross(a,b)<0)
    {
        tmid+=(2.0*pi);
    }
    if(cross(a,b)==0)
    {
        if((a.x==-b.x&&a.x!=0)||(a.y==-b.y&&a.y!=0))
        {
            tmid+=pi;
        }
    }
    
    res[(id<<1)-1]=tmid+deg;
    res[(id<<1)]=tmid-deg;
    
    return;
}

int main()
{
    C.x=0;
    C.y=0;
    
    cin>>n>>p[0].x>>p[0].y>>d>>t;
    for(int i=1;i<=n;i++)
    {
        cin>>p[i].x>>p[i].y;
    }
    
    for(int i=1;i<=n;i++)
    {
        solve(p[i],i);
    }
    
    tmax=-100;
    tmin=100;
    for(int i=1;i<=(n<<1);i++)
    {
        if(i>1)
        {
            while(res[i]-res[1]>=pi)
            {
                res[i]-=(2.0*pi);
            }
            while(res[1]-res[i]>=pi)
            {
                res[i]+=(2.0*pi);
            }
        }
        tmax=max(tmax,res[i]);
        tmin=min(tmin,res[i]);
    }
    
    while(tmax<=0.0)
    {
        tmax+=(2.0*pi);
        tmin+=(2.0*pi);
    }
    while(tmax>2.0*pi)
    {
        tmax-=(2.0*pi);
        tmin-=(2.0*pi);
    }
    
    k=(ll)(t/pi/(long double)2.0);
    ans=k*(tmax-tmin)+max((long double)0.0,min(t,k*(long double)2.0*pi+tmax)-max(k*(long double)2.0*pi,k*(long double)2.0*pi+tmin));
    
//    if(tmin<0.0)
//    {
//        ans+=tmin;
//    }
//    cout<<tmax<<" "<<tmin<<endl;
    printf("%.12Lf",ans);
    
    return 0;
}
/*
3
1 0
1
5
2 1
2 -1
5 0
*/