#include "iostream"
#include "algorithm"
#include "string"
#include "vector"
#include "cmath"
#include "bitset"
#include "queue"
#include "functional"
#include "map"
#include "unordered_map"
#include "set"
#include "stack"
 
#define lp(n) for (int i = 0; i < n; i++)
#define LP(n,i) for (int i = 0; i < n; i++)
#define mod 1000000007
#define sp ' '
#define intmax 2147483647
#define llmax 9223372036854775807
#define nyan "(=^･ω･^=)"
typedef long long ll;
using namespace std;

double x[3],y[3];
double abc[3],s;
int main(){
	lp(3)
		cin>>x[i]>>y[i];
	lp(3){
		abc[i]=sqrt((x[i]-x[(i+1)%3])*(x[i]-x[(i+1)%3])+(y[i]-y[(i+1)%3])*(y[i]-y[(i+1)%3]));
	}
	s=abs((x[1]-x[0])*(y[2]-y[0])-(x[2]-x[0])*(y[1]-y[0]))/2;
	printf("%.10f",2*s/(abc[0]+abc[1]+abc[2]+(4*s)/max({abc[0],abc[1],abc[2]})));
	return 0;
}
