#include <bits/stdc++.h>

using namespace std;

#define rep(i,a,b) for(int i =a; i <(b); ++i)

double dst = 1e9;

struct P { 
	double x, y;
    explicit P(double x = 0, double y = 0) : x(x), y(y) {}
	double cross(P p) {return x * p.y - y*p.x;}
	P operator-(P p) const {return P(x - p.x, y - p.y);}
	P operator+(P p) const {return P(x + p.x, y + p.y);}
	P operator/(double d) const {return P(x/d, y/d);}
	P perp() const { return P(-y, x); }
	double len() { return hypot(x, y); };
};

double dist(P a, P b, P c) {
	// thalet
	P side  = b - a;
	double len = side.len();
	P y = c - ((b + a) / 2);

	double res = abs(y.len() - (len / 2));

    // perp
    P perp = side.perp();
	res = min(res, abs(perp.cross(c - a)/len));
	res = min(res, abs(perp.cross(c - b)/len));

	return res;
}

int main() {
	cin.tie(0)->sync_with_stdio(0);
	cin.exceptions(cin.failbit);

	vector<P> p;
	rep(i, 0, 3) {
		double x, y;
		cin >> x >> y;
		p.push_back(P(x, y));
	};
	P A = p[0], B = p[1], C = p[2];

    double res = min({dist(A,B,C), dist(A, C, B), dist(C, B, A)});
	cout << setprecision(9) << res << endl;
}