#include<algorithm>
#include<iostream>
#include<cmath>
#include<vector>
using namespace std;
typedef long long lint;
typedef vector<int>vi;
typedef pair<int,int>pii;
#define rep(i,n)for(int i=0;i<(int)(n);++i)

double deg(const vector<pair<double,double> > &p){
  double pi=acos(-1.0);
  double cx=p[1].first-p[0].first;
  double cy=p[1].second-p[0].second;
  double bx=p[2].first-p[0].first;
  double by=p[2].second-p[0].second;
  double c=sqrt(bx*bx+by*by);
  double alpha2=atan2(cy,cx)-atan2(by,bx);
  if(alpha2<0){
    alpha2+=2*pi;
  }
  if(alpha2>=pi)
    alpha2=2*pi-alpha2;
  double alpha=alpha2/2;
  return alpha;
}

double f(const vector<pair<double,double> > &p){
  vector<pair<double,double> > q(p);
  swap(q[2],q[0]);
  double bx=p[2].first-p[0].first;
  double by=p[2].second-p[0].second;
  double c=sqrt(bx*bx+by*by);
  double alpha=deg(p);
  double beta=deg(q);
  double res=c/(1/tan(alpha)+1/tan(beta)+2);
  //cerr<<"res="<<res<<endl;
  return res;
}


int main(){
  vector<pair<double,double> > p(3);
  rep(i,3){
    double x,y;
    cin>>x>>y;
    p[i]=make_pair(x,y);
  }
  double ma=0;
  rep(i,3){
    vector<pair<double,double> > q(3);
    rep(j,3)q[j]=p[(i+j)%3];
    ma=max(ma,f(q));
  }
  printf("%.15f\n",ma);
}
