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();
        }
    }
}

Measured memory_bytes: 11220