#include <bits/stdc++.h>

const double EPS = 1e-8;
const double PI = acos(-1);
#define sqr(x) ((x) * (x))
#define equals(x, y) (fabs((x) - (y)) < EPS)
#define all(x) (x).begin(), (x).end()

const int N = 5;
int n;

struct Point {
  double x, y;
  Point(double x = 0, double y = 0) : x(x), y(y) { }
  bool operator == (const Point &rhs) const { return equals(x, rhs.x) && equals(y, rhs.y); }
};
using polygon = std::vector<Point>;
Point operator + (const Point& a, const Point& b) {
  return Point(a.x + b.x, a.y + b.y);
}
Point operator - (const Point& a, const Point& b) {
  return Point(a.x - b.x, a.y - b.y);
}
double dot(const Point& a, const Point& b) {
  return a.x * b.x + a.y * b.y;
}
double cross(const Point& a, const Point& b) {
  return a.x * b.y - a.y * b.x;
}
double dist(const Point& a, const Point& b) {
  return sqrt(sqr(a.x - b.x) + sqr(a.y - b.y));
}
Point polar(double a, double r) {
  return Point(r * cos(a), r * sin(a));
}
double arg(Point x) {
  return atan2(x.y, x.x);
}

struct Circle {
  Point o;
  double r;
  bool operator == (const Circle& rhs) const {
    return equals(o.x, rhs.o.x) && equals(o.y, rhs.o.y) && equals(r, rhs.r);
  }
  Circle() { }
  Circle(Point a, Point b) {
    o = a + b;
    o.x /= 2, o.y /= 2;
    r = dist(a, b) / 2;
  }
} c[N];
bool include(Circle a, Circle b) {
  return a.r + EPS > b.r + dist(a.o, b.o);
}
bool insection(Circle a, Circle b) {
  return !include(a, b) && !include(b, a) && a.r + b.r > dist(a.o, b.o) + EPS;
}
double adj(double a) {
  if (a > PI * 2 - EPS) a -= PI * 2;
  if (a < 0) a += PI * 2;
  return a;
}
std::pair<double, double> crossPoints(Circle a, Circle b) {
  double d = dist(a.o, b.o);
  double alpha = acos((sqr(d) + sqr(a.r) - sqr(b.r)) / (2 * a.r * d));
  double beta = adj(arg(b.o - a.o));
  return {adj(beta - alpha), adj(beta + alpha)};
}

int cnt[N];
double ans[N];
polygon g[N];

double solve() {
  for (int i = 1; i <= n; i++) {
    cnt[i] = ans[i] = 0;
    g[i].clear();
  }

  for (int i = 1; i <= n; i++)
    for (int j = 1; j <= n; j++) if (i != j)
      if (include(c[i], c[j])) ++cnt[j];

  for (int i = 1; i <= n; i++) {
    std::vector<std::pair<double, int>> vec;
    int cur = cnt[i]; 

    for (int j = 1; j <= n; j++) if (i != j) {
      if (!insection(c[i], c[j])) continue;
      auto [u, v] = crossPoints(c[i], c[j]);
      
      if (u > v) ++cur;
      vec.emplace_back(u, 1);
      vec.emplace_back(v, -1);
    }

    if (vec.empty()) {
      ans[cnt[i] + 1] += sqr(c[i].r) * PI;
      continue;
    }
    std::sort(all(vec));

    for (int j = 0; j < (int)vec.size(); j++) {
      double a = vec[j].first, b = vec[(j + 1) % vec.size()].first;
      cur += vec[j].second;
      double t = adj(b - a);
      ans[cur + 1] += 0.5 * sqr(c[i].r) * (t - sin(t));
      g[cur + 1].push_back(polar(a, c[i].r) + c[i].o);
      g[cur + 1].push_back(polar(b, c[i].r) + c[i].o);
    }
  }

  for (int i = 1; i <= n; i++)
    for (int j = 0; j < (int)g[i].size(); j += 2)
      ans[i] += cross(g[i][j], g[i][(j + 1) % g[i].size()]) / 2;
  for (int i = 1; i < n; i++)
    ans[i] -= ans[i + 1];
  return ans[1] + ans[2] + ans[3];
}

int main() {
  for (int t = 1; ; t++) {
    Point a, b, c, d;
    scanf("%lf%lf", &a.x, &a.y);
    scanf("%lf%lf", &b.x, &b.y);
    scanf("%lf%lf", &c.x, &c.y);
    scanf("%lf%lf", &d.x, &d.y);

    if (a == Point(0, 0) && b == Point(0, 0) && c == Point(0, 0) && d == Point(0, 0))
      break;
    
    n = 4;
    ::c[1] = Circle(a, c);
    ::c[2] = Circle(a, d);
    ::c[3] = Circle(b, c);
    ::c[4] = Circle(b, d);

    printf("Case %d: %.3f\n\n", t, solve());
  }
  return 0;
}