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

struct Point {
    double x, y, ang;
    Point() {};
    Point(double x, double y): x(x), y(y), ang(atan2(y, x)) {};

    Point operator+(Point p) {
        return Point(x+p.x, y+p.y);
    }
    Point operator-(Point p) {
        return Point(x-p.x, y-p.y);
    }
    double operator*(Point p) {
        return x*p.y-y*p.x;
    }
    bool operator<(Point p) {
        return ang < p.ang;
    }
    double len() {
        return sqrt(x*x+y*y);
    }
    Point unit() {
        double l = len();
        return Point(x/l, y/l);
    }
    Point ext(double l) {
        return Point(x*l, y*l);
    }
    Point rotate(double deg) {
        return Point(cos(deg)*x+sin(deg)*y, -sin(deg)*x+cos(deg)*y);
    }
};

pair<Point, Point> tangents(Point p, Point c, double r) {
    double s = (c-p).len();
    double l = sqrt(s*s-r*r);
    double d = atan2(r, l);
    Point u = (c-p).unit();
    return make_pair(u.rotate(d).ext(l), u.rotate(-d).ext(l));
};

double intersect(double l0, double r0, double l1, double r1) {
    return max(0.0, min(r0, r1) - max(l0, l1)); 
}

int main() {
#ifdef TEST
    freopen("zz.in", "r+", stdin);
#endif
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cout << setprecision(18);

    double PI = M_PIf64;
    double n, x0, y0, d, t; cin >> n >> x0 >> y0 >> d >> t;

    vector<Point> pts;
    for (int i = 0; i < n; ++ i) {
        int x, y; cin >> x >> y;
        auto [p0, p1] = tangents(Point(0, 0), Point(x, y), d);
        pts.push_back(p0), pts.push_back(p1);
    }

    double tg_d0, tg_d1;
    sort(pts.begin(), pts.end());
    for (int i = 0; i < pts.size(); ++ i) {
        if (pts.back().ang - pts[i].ang <= PI) {
            tg_d0 = pts[i].ang;
            tg_d1 = pts.back().ang;
            break;
        }
        pts[i].ang += 2 * PI;
        pts.push_back(pts[i]);
    }


    double res = 0;
    int ncyc = floor(t / (2 * PI));
    res += ncyc * (tg_d1 - tg_d0);
    t -= ncyc * (2 * PI);

    double nv_d0 = Point(x0, y0).ang;
    double nv_d1 = nv_d0 + t;
    res += intersect(tg_d0, tg_d1, nv_d0, nv_d1);
    res += intersect(tg_d0, tg_d1, nv_d0 + 2 * PI, nv_d1 + 2 * PI);
    cout << res << '\n';
}