#include <bits/stdc++.h>
#include <iostream>

using namespace std;

//double dist(double x1, double x2, double y1, double y2, double z1, double z2, double check1, double check2){
    
//}

int verify_one(int x1, int x2,int y1,int y2, int z1,int z2) {
    int zx1 = z1-x1;
    int zx2 = z2-x2;

    int zy1 = z1-y1;
    int zy2 = z2-y2;

    //cout << "scalar " << (zx1*zx2 + zy1*zy2)<< endl;

    return (zx1*zx2 + zy1*zy2 == 0);
}

int main(void){
    int x1,x2, y1,y2, z1,z2;
    cin >> x1 >> x2 >> y1 >> y2 >> z1 >> z2;
    //double ans = 1e9;


    cout << setprecision(10);

    //double hypot_min = std::numeric_limits<double>::max();

    double sxy1 = (x1+y1) / 2;
    double sxy2 = (x2+y2) / 2;

    double sxz1 = (x1+z1) / 2;
    double sxz2 = (x2+z2) / 2;

    double syz1 = (z1+y1) / 2;
    double syz2 = (z2+y2) / 2;

    double dxy = hypot(x1-y1, x2-y2);
    double dxz = hypot(x1-z1, x2-z2);
    double dyz = hypot(y1-z1, y2-z2);

    // X
    double dsx = hypot(x1-syz1, x2-syz2);

    // Y
    double dsy = hypot(y1-sxz1, y2-sxz2);

    // Z
    double dsz = hypot(z1-sxy1, z2-sxy2);

    double result_x = abs(dsx - (dyz/2));
    double result_y = abs(dsy - (dxz/2));
    double result_z = abs(dsz - (dxy/2));


    auto result = min(min(result_x, result_y), result_z);

    cout << abs(result) << endl;

    return 0;

}