#include <cstdio>
#include <algorithm>
#include <stack>
#include <queue>
#include <deque>
#include <vector>
#include <string>
#include <string.h>
#include <cstdlib>
#include <ctime>
#include <cmath>
#include <map>
#include <set>
#include <iostream>
#include <sstream>
#include <numeric>
#include <cctype>
#include <bitset>
#include <cassert>
#define fi first
#define se second
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define rrep(i,n) for(int i = 1; i <= (n); ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
#define gep(i,g,j) for(int i = g.head[j]; i != -1; i = g.e[i].next)
#define each(it,c) for(__typeof((c).begin()) it=(c).begin();it!=(c).end();it++)
#define rng(a) a.begin(),a.end()
#define maxs(x,y) x = max(x,y)
#define mins(x,y) x = min(x,y)
#define pb push_back
#define sz(x) (int)(x).size()
#define pcnt __builtin_popcount
#define uni(x) x.erase(unique(rng(x)),x.end())
#define snuke srand((unsigned)clock()+(unsigned)time(NULL));
#define df(x) int x = in()
#define dame { puts("-1"); return 0;}
#define show(x) cout<<#x<<" = "<<x<<endl;
#define PQ(T) priority_queue<T,vector<T>,greater<T> >
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<P> vp;
inline int in() { int x; scanf("%d",&x); return x;}
inline void priv(vi a) { rep(i,sz(a)) printf("%d%c",a[i],i==sz(a)-1?'\n':' ');}
template<typename T>istream& operator>>(istream&i,vector<T>&v)
{rep(j,sz(v))i>>v[j];return i;}
template<typename T>string join(vector<T>&v)
{stringstream s;rep(i,sz(v))s<<' '<<v[i];return s.str().substr(1);}
template<typename T>ostream& operator<<(ostream&o,vector<T>&v)
{if(sz(v))o<<join(v);return o;}
template<typename T1,typename T2>istream& operator>>(istream&i,pair<T1,T2>&v)
{return i>>v.fi>>v.se;}
template<typename T1,typename T2>ostream& operator<<(ostream&o,pair<T1,T2>&v)
{return o<<v.fi<<","<<v.se;}
const int MX = 100005, INF = 1001001001;
const ll LINF = 1e18;
const double eps = 1e-10;

// geom
#include <cmath>
const double inf = 1e6;
const double PI = acos(-1.0);
inline double toRad(double deg){ return deg * PI / 180.0;}

struct V {
  double x, y;
  V(double x=0, double y=0):x(x),y(y){}
  V operator+(V t) { return V(x+t.x,y+t.y);}
  V operator-(V t) { return V(x-t.x,y-t.y);}
  V operator*(double t) { return V(x*t,y*t);}
  V operator/(double t) { return V(x/t,y/t);}
  double dot(V t) { return x*t.x + y*t.y;}
  double cross(V t) { return x*t.y - y*t.x;}
  double norm2() { return x*x + y*y;}
  double norm() { return sqrt(x*x + y*y);}
  V rev() { return V(-x,-y);}
  V normalize() { return V(x/norm(), y/norm());}
  V rotate90() { return V(-y,x);}
  V rotate(V a, double rad){
    return V(a.x + cos(rad)*(x-a.x) - sin(rad)*(y-a.y),
             a.y + sin(rad)*(x-a.x) + cos(rad)*(y-a.y));
  }
  bool operator<(V a)const { return abs(x - a.x) > eps ? x < a.x : y < a.y;}
  bool operator==(V a)const { return abs(x - a.x) < eps && abs(y - a.y) < eps;}
};

struct Line {
  V s, t;
  Line(V s=V(0,0), V t=V(0,0)):s(s),t(t){}
  V dir() { return t-s;}
  V normalize() { return dir().normalize();}
  double norm() { return dir().norm();}
  /* +1: s-t,s-p : ccw
   * -1: s-t,s-p : cw
   * +2: t-s-p
   * -2: s-t-p
   *  0: s-p-t */
  int ccw(V p) {
    if (dir().cross(p-s) > eps) return +1;
    if (dir().cross(p-s) < -eps) return -1;
    if (dir().dot(p-s) < -eps) return +2;
    if (dir().norm()+eps < (p-s).norm()) return -2;
    return 0;
  }
  Line operator+(V a) { return Line(s+a,t+a);}
  Line operator-(V a) { return Line(s-a,t-a);}
  bool touch(Line l) {
    int a = ccw(l.s)*ccw(l.t), b = l.ccw(s)*l.ccw(t);
    return !a || !b || (a == -1 && b == -1);
  }
  double distLP(V p) { return abs(dir().cross(p-s)/norm());}
  double distSP(V p) {
    if (dir().dot(p-s) < eps) return (p-s).norm();
    if (dir().rev().dot(p-t) < eps) return (p-t).norm();
    return distLP(p);
  }
  double distSS(Line l) {
    if(touch(l)) return 0;
    return min(min(distSP(l.s),distSP(l.t)),min(l.distSP(s),l.distSP(t)));
  }
  V proj(V p) {
    double a = (p-s).dot(dir())/dir().norm2();
    return s + dir()*a;
  }
  Line mid() {
    V p = (s+t)/2, q = dir();
    return Line(p, p+V(q.y,-q.x));
  }
  V xp(Line l) {
    V a = dir(), b = l.dir();
    if (abs(b.cross(a)) < eps) return V(inf,inf);
    return s + a*(b.cross(l.s-s)/b.cross(a));
  }
};

typedef vector<V> Poly;
inline V pnxt(Poly& p, int i) { return p[(i+1)%sz(p)];}
inline V ppre(Poly& p, int i) { return p[(i-1+sz(p))%sz(p)];}
inline Line pline(Poly& p, int i) { return Line(p[i],pnxt(p,i));}
// geom

Line gl(Poly p, double r) {
  Line l = pline(p,0);
  Line res = l-l.dir().rotate90().normalize()*r;
  // printf("%.02f %.02f %.02f %.02f\n",l.s.x,l.s.y,l.t.x,l.t.y);
  // printf("%.02f %.02f %.02f %.02f\n",res.s.x,res.s.y,res.t.x,res.t.y);
  return res;
}

bool f(Poly p, double r) {
  vector<Line> ls;
  rep(i,3) {
    ls.pb(gl(p,r));
    rotate(p.begin(),p.begin()+1,p.end());
  }
  ls.pb(ls[0]);
  double mx = 0;
  Poly ps;
  rep(i,3) {
    ps.pb(ls[i].xp(ls[i+1]));
  }
  // rep(i,3) printf("%.3f %.3f\n",ps[i].x,ps[i].y);
  // cout<<ls[0].ccw(ps[1])<<endl;
  if (ls[0].ccw(ps[1]) == 1) return false;
  ps.pb(ps[0]);
  rep(i,3) {
    maxs(mx, (ps[i]-ps[i+1]).norm());
  }
  return mx > r*2;
}

int main() {
  Poly p(3);
  rep(i,3) {
    cin >> p[i].x >> p[i].y;
  }
  if (pline(p,0).ccw(p[2]) == 1) reverse(rng(p));
  // f(p,0.1); return 0;
  double ans = 0;
  rep(ri,3) {
    double l = 0, r = 10000;
    rep(ti,100) {
      double c = (l+r)/2;
      if (f(p,c)) l = c; else r = c;
    }
    rotate(p.begin(),p.begin()+1,p.end());
    maxs(ans,l);
  }
  printf("%.10f\n",ans);
  return 0;
}































Measured memory_bytes: 256