using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;
using System.Runtime.Remoting.Contexts;
using System.Security.Cryptography.X509Certificates;
namespace Contest
{
class Scanner
{
private string[] line = new string[0];
private int index = 0;
public string Next()
{
if (line.Length <= index)
{
line = Console.ReadLine().Split(' ');
index = 0;
}
var res = line[index];
index++;
return res;
}
public int NextInt()
{
return int.Parse(Next());
}
public long NextLong()
{
return long.Parse(Next());
}
public string[] Array()
{
line = Console.ReadLine().Split(' ');
index = line.Length;
return line;
}
public int[] IntArray()
{
var array = Array();
var result = new int[array.Length];
for (int i = 0; i < array.Length; i++)
{
result[i] = int.Parse(array[i]);
}
return result;
}
public long[] LongArray()
{
var array = Array();
var result = new long[array.Length];
for (int i = 0; i < array.Length; i++)
{
result[i] = long.Parse(array[i]);
}
return result;
}
}
struct P
{
public double X, Y;
public P(double x, double y)
{
X = x;
Y = y;
}
}
class Program
{
private P A, B, C;
private double a, b, c;
private void Scan()
{
var sc = new Scanner();
A = new P(sc.NextInt(), sc.NextInt());
B = new P(sc.NextInt(), sc.NextInt());
C = new P(sc.NextInt(), sc.NextInt());
}
public void Solve()
{
Scan();
a = Dist(B, C);
b = Dist(C, A);
c = Dist(A, B);
double s = S(A, B, C);
double r = s / (a + b + c) * 2;
double min = 0;
double max = r;
double l = Math.Max(Math.Max(a, b), c);
for (int i = 0; i < 10000; i++)
{
double mid = (min + max) / 2;
if (mid * 2 < l * (1 - (mid / r)))
{
min = mid;
}
else
{
max = mid;
}
}
Console.WriteLine(min);
}
private double S(P one, P two, P three)
{
return S(new P(two.X - one.X, two.Y - one.Y), new P(three.X - one.X, three.Y - one.Y));
}
private double S(P one, P two)
{
return Math.Abs(one.X * two.Y - one.Y * two.X) / 2;
}
private double Dist(P one, P two)
{
return Math.Sqrt((one.X - two.X) * (one.X - two.X) + (one.Y - two.Y) * (one.Y - two.Y));
}
static void Main(string[] args)
{
new Program().Solve();
}
}
}