import java.util.Scanner;


public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        double x = sc.nextInt();
        double y = sc.nextInt();
        double x1 = sc.nextInt();
        double y1 = sc.nextInt();
        double x2 = sc.nextInt();
        double y2 = sc.nextInt();

        double xv = x2-x1;
        double yv = y2-y1;
        double xv2 = x-x1;
        double yv2 = y-y1;
        double SP = (xv*xv2)+(yv*yv2);

        double xv1 = x1-x2;
        double yv1 = y1-y2;
        double xv21 = x-x2;
        double yv21 = y-y2;
        double SP1 = (xv1* xv21)+(yv1*yv21);

        double a = y1-y2;
        double b = x2-x1;
        double c = (x1*y2)-(x2*y1);

        if ((SP1 >= 0) && SP >= 0){
            double AP = Math.abs(a*x+b*y+c)/Math.sqrt((a*a)+b*b);
            System.out.println(AP);
        } else {
            double vnx = x2-x;
            double vny = y2-y;
            double vnx1 = x1-x;
            double vny1 = y1-y;
            double ga1 = Math.sqrt((vnx*vnx)+(vny*vny));
            double ga2 = Math.sqrt((vnx1*vnx1)+(vny1*vny1));

            if (ga1 < ga2){
                System.out.println(ga1);
            } else {
                System.out.println(ga2);
            }
        }
    }
}