#include "bits/stdc++.h"
using namespace std;

int main() {
	double x1, x2, x3, y1, y2, y3, a, b, c, M, S, r, X;
	cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;
	a = (x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2);
	a = sqrt(a);
	b = (x2 - x3) * (x2 - x3) + (y2 - y3) * (y2 - y3);
	b= sqrt(b);
	c = (x3 - x1) * (x3 - x1) + (y3 - y1) * (y3 - y1);
	c = sqrt(c);
	S = 0.25 * sqrt((a + b + c) * (-a + b + c) * (a - b + c) * (a + b - c));
	r = 2 * S / (a + b + c);
	M = max(max(a, b), c);
	X = 2 / M + 1 / r;
	X = 1 / X;
	printf("%.12f", X);
}