#include <iostream>
#include <cmath>
using namespace std;
struct Point {
	double x,y;
	void read()
	{
		scanf("%lf%lf",&x,&y);
	}
	Point operator-(Point a)
	{
		Point res;
		res.x=x-a.x;
		res.y=y-a.y;
		return res;
	}
	double operator*(Point a)
	{
		return x*a.y-y*a.x;
	}

	double scal(Point a)
	{
		return x*a.x+y*a.y;
	}

	double dist(Point a)
	{
		return sqrt((a.x-x)*(a.x-x) + (a.y-y)*(a.y-y));
	}


};
int main()
{
//	freopen("distance.in","r",stdin);
//	freopen("distance2.out","w",stdout);
	Point p1,p2,p;
	p.read();
	p1.read(); p2.read();
	if ((p2-p1).scal(p-p1) >= 0 && (p-p2).scal(p1-p2) >= 0) printf("%.6lf",abs((p2-p1)*(p-p1))/p2.dist(p1)); else printf("%.6lf",min(p.dist(p1),p.dist(p2)));

}