#include<bits/stdc++.h>
using namespace std;
const int N=105;
typedef long double db;
const db eps = 1e-8;
const db pi = acos(-1.0);
int n,d;
db xx0,yy0,t;
db px[N],py[N];
db the[N],theh[N];
db pin[N],pout[N];
db in,out,now,ans,dlt;
int main(){
//	freopen("ex.in","r",stdin);
//	scanf("%d%lf%lf%d%lf",&n,&xx0,&yy0,&d,&t);
	cin>>n>>xx0>>yy0>>d>>t;
	for(int i=1;i<=n;i++){
//		scanf("%lf%lf",&px[i],&py[i]);
		cin>>px[i]>>py[i];
		theh[i]=asin(d/sqrt((px[i]*px[i]+py[i]*py[i])));
		the[i]=atan2(py[i],px[i]);
		pin[i]=the[i]-theh[i];
		if(pin[i]<=-pi) pin[i]+=2*pi;
		pout[i]=the[i]+theh[i];
		if(pout[i]<=-pi) pout[i]+=2*pi;
//		printf("%lf %lf ",the[i],theh[i]);
//		printf("%lf %lf\n",pin[i],pout[i]);
	}
	in=pin[1];out=pout[1];
	for(int i=2;i<=n;i++){
		in=min(in,pin[i]);
		out=max(out,pout[i]);
	}
	now = atan2(yy0,xx0);
	if(now <= -pi) now += 2*pi;
	dlt = out - in;
	while(dlt <= -pi) dlt += 2*pi;
	while(t>2*pi){
		t-=2*pi;
		ans += dlt;
	}
	while(out < in) out +=2*pi;
//	printf("%lf %lf\n",in,out);
//	printf("%lf\n",now);
//	printf("%lf\n",ans);
	in -= now;
	out -= now;
	if(t>=out){
		ans += out - max<db>(in,0.0);
	}else if(t>=in){
		ans += t - max<db>(in,0.0);
	}
	printf("%.10lf",double(ans));
	return 0;
}