#include<iostream>
#include<cmath>
using namespace std;
int dis(int e, int d);

int main()
{
	double x1, x2, x3, y4, y2, y3;
	cin >> x1 >> y4;
	cin >> x2 >> y2;
	cin >> x3 >> y3;
	double X1 = abs(x1 - x2);
	double X2 = abs(x1 - x3);
	double X3 = abs(x2 - x3);
	double Y1 = abs(y4 - y2);
	double Y2 = abs(y4 - y3);
	double Y3 = abs(y2 - y3);
	double c1, c2, c3, c4;
	c1 = dis(X1, Y1);
	c2 = dis(X2, Y2);
	c3 = dis(X3, Y3);

	c4 = c1 + c2 + c3;

	printf("%.2lf", c4);

	return 0;
}
int dis(int e,int d)
{
	int c;
	c = sqrt((e * e) + (d * d));
	
		return c;
}