#include<iostream>
#include<algorithm>
#include<vector>
#include<queue>
#include<math.h>
#include<complex>
#include<iomanip>
#define lol(i,n) for(int i=0;i<n;i++)
#define mod 1000000007
typedef long long ll;
using namespace std;
double dis(double x1,double x2,double y1,double y2){
	return sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));
}
int main(){
	double x[3],y[3];
	lol(i,3)cin>>x[i]>>y[i];
	lol(i,2)x[i]-=x[2],y[i]-=y[2];x[2]=0,y[2]=0;
	double a=dis(x[0],x[1],y[0],y[1]);
	double b=dis(x[0],x[2],y[0],y[2]);
	double c=dis(x[1],x[2],y[1],y[2]);
	double w=max(a,max(b,c))*0.5;
	double h=abs(x[0]*y[1]-x[1]*y[0])/(a+b+c);
	double r=h*w/(h+w);
	cout<<fixed<<setprecision(10)<<r<<endl;
	return 0;
}
