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

using namespace std;

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


    cout << setprecision(10);

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

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

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

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

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

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

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

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

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


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

    cout << abs(result) << endl;

    return 0;

}