#include <bits/stdc++.h>

using namespace std;
typedef long double ld;

const ld pi = acosl(-1), eps = 1e-9;
struct vec
{
	ld x, y;
	vec(ld x0 = 0, ld y0 = 0)
	{
		x = x0;
		y = y0;
	}
	vec operator + (vec v)
	{
		return vec(x + v.x, y + v.y);
	}
	vec operator - (vec v)
	{
		return vec(x - v.x, y - v.y);
	}
	vec operator * (ld k)
	{
		return vec(x * k, y * k);
	}
	ld dis2()
	{
		return x * x + y * y;
	}
	void print()
	{
		printf("(%.10Lf, %.10Lf)\n", x, y);
	}
};
vec p[105];
pair<vec, vec> haha(vec a, ld b, vec c, ld d) // b, d is dis^2
{
	c = c - a;
	ld p = (c.dis2() - d + b) / 2, x, y, u, v, w;
	ld x0, x1;
	if(abs(c.y) < eps)
	{
		x = p / c.x;
		y = sqrtl(b - x * x);
		return make_pair(a + vec(x, y), a + vec(x, -y));
	}
	u = c.dis2();
	v = -2 * p * c.x;
	w = p * p - b * c.y * c.y;
	x0 = (-v + sqrtl(v * v - 4 * u * w)) / (2 * u);
	x1 = (-v - sqrtl(v * v - 4 * u * w)) / (2 * u);
	return make_pair(a + vec(x0, (p - c.x * x0) / c.y), a + vec(x1, (p - c.x * x1) / c.y));
}

int main()
{
	int n, x0, y0, d, t, i;
	vec u, v;
	ld l, r, L, R, pl, pr, ans = 0;
	L = 2 * pi;
	R = 0;
	scanf("%d%d%d%d%d", &n, &x0, &y0, &d, &t);
	pl = atan2(y0, x0);
	for(i = 1; i <= n; i++)
	{
		scanf("%Lf%Lf", &p[i].x, &p[i].y);
		u = (vec(0, 0) + p[i]) * 0.5;
		auto o = haha(vec(0, 0), (ld)d * d, u, u.dis2());
		u = o.first;
		v = o.second;
		// printf("#%d\n", i);
		// u.print();
		// v.print();
		if(u.x * v.y < u.y * v.x)
			swap(u, v);
		l = atan2(v.y, v.x) - pi / 2;
		r = atan2(u.y, u.x) + pi / 2;
		// printf("#%.10Lf %.10Lf\n", l, r);
		L = min(L, l);
		R = max(R, r);
	}
	pr = pl + t;
	for(i = 0; i < 10000; i++)
		if(max(L + i * 2 * pi, pl) < min(R + i * 2 * pi, pr))
			ans += min(R + i * 2 * pi, pr) - max(L + i * 2 * pi, pl);
	printf("%.10Lf\n", ans);
	return 0;
}
/*
3 1 0 1 1
1 2
2 1
2 2
*/