#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
#include<vector>
#include<queue>
#include<functional>
#include<utility>
#include<cassert>
using namespace std;
const int N = 111;
#define pi acos(-1)
int n;
struct vec{
    double x,y;
}a[N],sl[N << 1];
double sx,sy,d,t;
inline double Dis(vec a,vec b){
    return 1.0 * sqrt((a.y - b.y) * (a.y - b.y) + (a.x - b.x) * (a.x - b.x));
}
bool cmp(vec u,vec v){
    if(u.x != v.x) return u.x < v.x;
    return u.y < v.y;
}
int main(){
    int i,j,k,x,y;
    vec O = {0,0};
    scanf("%d %lf %lf %lf %lf",&n,&sx,&sy,&d,&t);
    for(i = 1;i <= n;i++){
        scanf("%lf %lf",&a[i].x,&a[i].y);
    }
    for(i = 1;i <= n;i++){
        double p = atan2(a[i].y,a[i].x);
        double q = abs(acos(d / Dis(a[i],O)));
        sl[i].x = p + q - pi / 2,sl[i].y = p - q + pi / 2;
        //printf("%lf %lf\n",sl[i].x,sl[i].y);
    }
    sort(sl + 1,sl + n + 1,cmp);
    for(i = 1;i <= n;i++) sl[i + n] = {sl[i].x + 2 * pi,sl[i].y + 2 * pi};
    double res1,res2,res;
    for(i = 1;i <= n;i++){
        if(sl[n + i - 1].y - sl[i].x <= pi){
            res1 = sl[n + i - 1].y - sl[i].x;
            k = i;
            break;
        }
    }
    res = (int)(t / 2 / pi) * res1;
    t -= 2 * pi * (int)(t / 2 / pi);
    double st = atan2(sy,sx);
    //printf("%lf %lf %lf\n",st,sl[k].x,sl[n + k - 1].y);
    if(sl[n + k - 1].y - st > 2 * pi) st += 2 * pi;
    if(st < sl[k].x) res += min(res1,max(0.0,t - (sl[k].x - st)));
    else if(st <= sl[n + k - 1].y) res += min(sl[n + k - 1].y - st,t);
    else res += min(res1,max(0.0,t - (sl[k].x + 2 * pi - st)));
    printf("%.12lf\n",res);
    return 0;
}