#include<bits/stdc++.h>
#define int long long
using namespace std;

signed main()
{
    double x1,y1,x2,y2,x3,y3; cin>>x1>>y1>>x2>>y2>>x3>>y3;

    double a=hypot(abs(x1-x2),abs(y1-y2));
    double b=hypot(abs(x2-x3),abs(y2-y3));
    double c=hypot(abs(x3-x1),abs(y3-y1));
    
    double s=(a+b+c)/2;
    double S=sqrt(s*(s-a)*(s-b)*(s-c));
    double r=S/s;

    double M=max({a,b,c});
    double ans=(M*r)/(2*r+M);

    cout<<fixed<<setprecision(10)<<ans<<endl;
}
