#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
typedef long double LB;
const LL MOD=1e9+7;
const LL INF=1e9;
const LB eps=1e-10;
int n;
LB X0,Y0,d,t,X[105],Y[105],enter[105],leave[105],ans;
signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(0),cout.tie(0);
    cin >> n >> X0 >> Y0 >> d >> t;
    LB em=acos(-1)*2,lm=0;
    for (int i=1;i<=n;i++)
    {
        cin >> X[i] >> Y[i];
        LB l=sqrt(X[i]*X[i]+Y[i]*Y[i]),
               ang=atan2(Y[i],X[i]);
        if (ang<0) ang+=acos(-1)*2;
        LB ang1=asin(d/l);
        enter[i]=ang-ang1;
        leave[i]=ang+ang1;
        em=min(em,enter[i]);
        lm=max(lm,leave[i]);
    }
    LB start=atan2(Y0,X0);
    if (start<0) start+=acos(-1)*2;
    LB em2=max(em,start),
           lm2=max(lm,start);
    if (t-(em2-start)>0) ans+=min(t-(em2-start),lm2-em2);
    t-=acos(-1)*2-start;
    while (t>em)
    {
        ans+=min(t-em,lm-em);
        t-=acos(-1)*2;
    }
    cout << fixed << setprecision(9) << ans << '\n';
    return 0;
}