#include<bits/stdc++.h>
using namespace std;
const long double pi=acos(-1);
struct point {
	long double x,y;
};
long double dist(point u,point v){
	return sqrt((u.x-v.x)*(u.x-v.y)+(u.y-v.y)*(u.y-v.y));
}
long double g(long double x){
	if(x<0.0) x+=2*pi;
	if(x>2*pi) x-=2*pi;
	return x;
}
int n,d,t;
int main(){
	point o;
	cin>>n>>o.x>>o.y>>d>>t;
	point a[n+10];
	for(int i=1;i<=n;i++){
		cin>>a[i].x>>a[i].y;
	}
	long double start=atan2(o.y,o.x);
	if(start<0) start+=2*pi;
	vector<long double>b,c;
	for(int i=1;i<=n;i++){
		long double ang=atan2(a[i].y,a[i].x);
		if(ang<0) ang+=2*pi;
		long double now=atan2(d,sqrt(dist(a[i],{0,0})*dist(a[i],{0,0})-d*d));
		b.push_back(g(ang+now));
		c.push_back(g(ang-now));
	}
	sort(b.begin(),b.end());
	sort(c.begin(),c.end());
	for(int i=1;i<n;i++){
		if(b[i]-b[i-1]>pi){
			for(int j=0;j<i;j++){
				b[j]+=2*pi;
			}
			break;
		}
	}
	for(int i=1;i<n;i++){
		if(c[i]-c[i-1]>pi){
			for(int j=0;j<i;j++){
				c[j]+=2*pi;
			}
			break;
		}
	}
	sort(b.begin(),b.end());
	sort(c.begin(),c.end());
	long double l=c[0],r=b[n-1];
	if(l>r) r+=2*pi;
	if(r>2*pi) l-=2*pi,r-=2*pi;
	auto f=[&](long double now)->long double{
		long long k=now/(2*pi);
		long double ans=(r-l)*k;
		now-=pi*2*k;
		if(now>r) ans+=r-max((long double)0.0,l);
		if(now<=r&&now>=max((long double)0.0,l)) ans+=now-max((long double)0.0,l);
		return ans;
	};
	printf("%.10Lf\n",f(start+t)-f(start));
	return 0;
}