Problem: Qwerty the Ranger arrived to the Diatar system with a very important task. He should deliver a special carcinogen for scientific research to planet Persephone. This is urgent, so Qwerty has to get to the planet as soon as possible. A lost day may fail negotiations as nobody is going to pay for an overdue carcinogen.

You can consider Qwerty's ship, the planet Persephone and the star Diatar points on a plane. Diatar is located in the origin of coordinate axes — at point (0, 0). Persephone goes round Diatar along a circular orbit with radius R in the counter-clockwise direction at constant linear speed vp (thus, for instance, a full circle around the star takes <image> of time). At the initial moment of time Persephone is located at point (xp, yp).

At the initial moment of time Qwerty's ship is at point (x, y). Qwerty can move in any direction at speed of at most v (v > vp). The star Diatar is hot (as all stars), so Qwerty can't get too close to it. The ship's metal sheathing melts at distance r (r < R) from the star.

Find the minimum time Qwerty needs to get the carcinogen to planet Persephone.

Input

The first line contains space-separated integers xp, yp and vp ( - 104 ≤ xp, yp ≤ 104, 1 ≤ vp < 104) — Persephone's initial position and the speed at which it goes round Diatar.

The second line contains space-separated integers x, y, v and r ( - 104 ≤ x, y ≤ 104, 1 < v ≤ 104, 1 ≤ r ≤ 104) — The intial position of Qwerty's ship, its maximum speed and the minimum safe distance to star Diatar.

It is guaranteed that r2 < x2 + y2, r2 < xp2 + yp2 and vp < v.

Output

Print a single real number — the minimum possible delivery time. The answer will be considered valid if its absolute or relative error does not exceed 10 - 6.

Examples

Input

10 0 1
-10 0 2 8


Output

9.584544103

Input

50 60 10
50 60 20 40


Output

0.000000000

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
template <typename S, typename T>
ostream& operator<<(ostream& out, pair<S, T> const& p) {
  out << '(' << p.first << ", " << p.second << ')';
  return out;
}
template <typename T>
ostream& operator<<(ostream& out, vector<T> const& v) {
  int l = v.size();
  for (int i = 0; i < l - 1; i++) out << v[i] << ' ';
  if (l > 0) out << v[l - 1];
  return out;
}
void tr() { cout << endl; }
template <typename S, typename... Strings>
void tr(S x, const Strings&... rest) {
  cout << x << ' ';
  tr(rest...);
}
long double xp, yp, vp;
long double x, y, v, r;
long double R, w;
const long double PI = 3.1415926535897932384626433832795;
long double eps = 1e-9;
long double dist(long double x1, long double y1, long double x2,
                 long double y2) {
  long double dx = x1 - x2, dy = y1 - y2;
  return (long double)sqrt(dx * dx + dy * dy);
}
long double distPointFromLine(long double x0, long double y0, long double x1,
                              long double y1, long double x2, long double y2) {
  return abs((y2 - y1) * x0 - (x2 - x1) * y0 + x2 * y1 - y2 * x1);
}
long double angleBetweenVectors(long double u1, long double u2, long double v1,
                                long double v2) {
  return acos((u1 * v1 + u2 * v2) / dist(0, 0, u1, u2) / dist(0, 0, v1, v2));
}
bool isAcute(long double u1, long double u2, long double v1, long double v2) {
  return (u1 * v1 + u2 * v2 > 0);
}
long double distWithCircle(long double x1, long double y1, long double x2,
                           long double y2) {
  if (dist(x1, y1, x2, y2) < eps) return 0;
  long double d = distPointFromLine(0, 0, x1, y1, x2, y2);
  if (d >= r * dist(x1, y1, x2, y2)) return dist(x1, y1, x2, y2);
  if (!isAcute(-x1, -y1, x2 - x1, y2 - y1) or
      !isAcute(-x2, -y2, x1 - x2, y1 - y2))
    return dist(x1, y1, x2, y2);
  long double d1 = dist(0, 0, x1, y1);
  long double d2 = dist(0, 0, x2, y2);
  long double d3 = sqrt(d1 * d1 - r * r);
  long double d4 = sqrt(d2 * d2 - r * r);
  long double ang1 = angleBetweenVectors(-x1, -y1, x2 - x1, y2 - y1);
  long double ang2 = angleBetweenVectors(-x2, -y2, x1 - x2, y1 - y2);
  long double ang3 = acos((long double)r / d1);
  long double ang4 = acos((long double)r / d2);
  long double ang = PI - ang1 - ang2 - ang3 - ang4;
  return d3 + d4 + r * ang;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  cin >> xp >> yp >> vp;
  cin >> x >> y >> v >> r;
  R = dist(0, 0, xp, yp);
  w = vp / R;
  if (dist(xp, yp, x, y) < eps) {
    cout << setprecision(11) << fixed << 0 << endl;
    return 0;
  }
  long double lo = 0, hi = 1e9, t;
  for (int i = 0; i < 100; i++) {
    t = (lo + hi) / 2;
    long double wt = w * t;
    long double nx = xp * cos(wt) - yp * sin(wt);
    long double ny = yp * cos(wt) + xp * sin(wt);
    long double d = distWithCircle(x, y, nx, ny);
    if (d <= v * t)
      hi = t;
    else
      lo = t;
  }
  cout << setprecision(11) << fixed << lo << endl;
  return 0;
}