#include <bits/stdc++.h>
#include <cmath>
using namespace std;

double diff(double Ax, double Ay, double Bx, double By, double Cx, double Cy) {
    double Sx = (Ax + Bx) / 2;
    double Sy = (Ay + By) / 2;
    double R2 = ((Ax - Bx) * (Ax - Bx) + (Ay - By) * (Ay - By)) / 4;
    //cout << "R2 " << R2 << endl;
    Cx -= Sx;
    Cy -= Sy;
    double x = sqrt(R2 / (1 + (Cy/Cx)*(Cy/Cx)));
    double y = (Cy/Cx)*x;
    //cout << "C " << Cx << " " << Cy << endl;
    //cout << "xy " << x << " " << y << endl;
    return min(sqrt((Cx-x)*(Cx-x) + (Cy-y)*(Cy-y)), sqrt((Cx+x)*(Cx+x) + (Cy+y)*(Cy+y)));
}

int main() {
    double Ax, Ay, Bx, By, Cx, Cy;
    cin >> Ax >> Ay >> Bx >> By >> Cx >> Cy;
    //cout << diff(Ax, Ay, Bx, By, Cx, Cy) << ", " << diff(Ax, Ay, Cx, Cy, Bx, By) << ", " << diff(Bx, By, Cx, Cy, Ax, Ay) << endl;
    double res = diff(Ax, Ay, Bx, By, Cx, Cy);
    res = min(res, diff(Ax, Ay, Cx, Cy, Bx, By));
    res = min(res, diff(Bx, By, Cx, Cy, Ax, Ay));
    cout << res << endl;
}