#include <iostream>
#include <complex>
#include <utility>
#include <cstdio>
#include <vector>

using namespace std;

typedef complex<double> POS;
typedef pair<POS, POS> LINE;

POS TABLE[32][32];
int N;

POS CrossPoint(const LINE& l1, const LINE& l2)
{
  POS p1 = l1.first;
  POS p2 = l1.second;
  POS p3 = l2.first;
  POS p4 = l2.second;
  POS rot = polar(1.0, 1.0);
  p1 *= rot;
  p2 *= rot;
  p3 *= rot;
  p4 *= rot;
  double a1, b1, a2, b2;
  {
    double x1 = p1.real();
    double y1 = p1.imag();
    double x2 = p2.real();
    double y2 = p2.imag();
    a1 = (y2 - y1) / (x2 - x1);
    b1 = y1 - a1 * x1;
  }
  {
    double x1 = p3.real();
    double y1 = p3.imag();
    double x2 = p4.real();
    double y2 = p4.imag();
    a2 = (y2 - y1) / (x2 - x1);
    b2 = y1 - a2 * x1;
  }
  double x = (b2 - b1) / (a1 - a2);
  double y = a1 * x + b1;
  POS res(x, y);
  res /= rot;
  return res;
}

double CalcArea(const vector<POS>& v)
{
  double res = 0.0;
  for (int i = 0; i < (int)v.size() - 1; ++i){
    res += v[i].real() * v[i + 1].imag() - v[i].imag() * v[i + 1].real();
  }
  res /= 2.0;
  return res;
}

double Calc(int x, int y)
{
  vector<POS> v;
  v.push_back(TABLE[x][y]);
  v.push_back(TABLE[x + 1][y]);
  v.push_back(TABLE[x + 1][y + 1]);
  v.push_back(TABLE[x][y + 1]);
  v.push_back(TABLE[x][y]);
  return CalcArea(v);
}

void Input()
{
  int n = N;
  TABLE[0][0] = POS(0, 0);
  TABLE[0][n + 1] = POS(0, 1);
  TABLE[n + 1][0] = POS(1, 0);
  TABLE[n + 1][n + 1] = POS(1, 1);
  for (int i = 1; i <= n; ++i){
    double a;
    cin >> a;
    TABLE[i][0] = POS(a, 0);
  }
  for (int i = 1; i <= n; ++i){
    double b;
    cin >> b;
    TABLE[i][n + 1] = POS(b, 1);
  }
  for (int i = 1; i <= n; ++i){
    double c;
    cin >> c;
    TABLE[0][i] = POS(0, c);
  }
  for (int i = 1; i <= n; ++i){
    double d;
    cin >> d;
    TABLE[n + 1][i] = POS(1, d);
  }
}

void FillCrossPoint()
{
  int n = N;
  for (int x = 1; x <= N; ++x){
    for (int y = 1; y <= N; ++y){
      LINE l1 = make_pair(TABLE[x][0], TABLE[x][n + 1]);
      LINE l2 = make_pair(TABLE[0][y], TABLE[n + 1][y]);
      TABLE[x][y] = CrossPoint(l1, l2);
    }
  }
}

main()
{
  while (cin >> N && N){
    Input();
    FillCrossPoint();
    double answer = -1.0;
    for (int x = 0; x <= N; ++x){
      for (int y = 0; y <= N; ++y){
	answer = max(answer, Calc(x, y));
      }
    }
    printf("%.06lf\n", answer);
  }
}