Problem: Snuke received a triangle as a birthday present. The coordinates of the three vertices were (x_1, y_1), (x_2, y_2), and (x_3, y_3).

He wants to draw two circles with the same radius inside the triangle such that the two circles do not overlap (but they may touch). Compute the maximum possible radius of the circles.

Constraints

* 0 ≤ x_i, y_i ≤ 1000
* The coordinates are integers.
* The three points are not on the same line.

Input

The input is given from Standard Input in the following format:


x_1 y_1
x_2 y_2
x_3 y_3


Output

Print the maximum possible radius of the circles. The absolute error or the relative error must be at most 10^{-9}.

Examples

Input

0 0
1 1
2 0


Output

0.292893218813


Input

3 1
1 5
4 9


Output

0.889055514217

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
#define fi first
#define se second
template<typename A, typename B> inline bool chmax(A &a, B b) { if (a<b) { a=b; return 1; } return 0; }
template<typename A, typename B> inline bool chmin(A &a, B b) { if (a>b) { a=b; return 1; } return 0; }
typedef long long ll;
typedef pair<int, int> pii;
const ll INF = 1ll<<30;
const ll longINF = 1ll<<60;
const ll MOD = 1000000007;
const double EPS = 1e-9;
const bool debug = 0;
//---------------------------------//

typedef complex<double> Vec;

double dot(Vec a, Vec b) {
	return a.real() * b.real() + a.imag() * b.imag();
}
double cross(Vec a, Vec b) {
	return a.real() * b.imag() - a.imag() * b.real();
}

Vec ver[3];

bool solve(double R) {
	double S = abs(cross(ver[2] - ver[0], ver[1] - ver[0]) / 2.0);
	double edlen[3];
	REP(i, 3) edlen[i] = abs(ver[(i + 1) % 3] - ver[i]);
	double inr = 2*S / accumulate(edlen, edlen + 3, 0.0);
	// inr : inr - R
	if (inr <= R) return false;
	
	double mxlen = *max_element(edlen, edlen + 3);
	
	double aflen = mxlen * (inr - R) / inr;
	return aflen >= 2 * R;
}

int main() {
	REP(i, 3) {
		int x, y;
		scanf("%d %d", &x, &y);
		ver[i] = Vec(x, y);
	}
	
	double l = 0, r = 1000;
	REP(i, 100) {
		double m = (l + r) / 2;
		if (solve(m)) l = m;
		else r = m;
	}
	
	printf("%.15f\n", l);
	
	return 0;
}