#include<iostream>
#include<math.h>
using namespace std;
class Position
{
public:
	int x;
	int y;
};
int Distance(Position a, Position b )
{
	int dis = 0;
	dis = (a.x - b.x) * (a.x - b.x) + (a.y - b.y) * (a.y - b.y);
	dis = sqrt(dis);
	return dis;
}

int main()
{
	Position a, b, c;
	cin >> a.x>>a.y;
	cin >> b.x >> b.y;
	cin >> c.x >> c.y;
	int dis1 = Distance(a, b);
	int dis2 = Distance(a, c);
	int dis3 = Distance(b, c);
	float Dis=(float)( dis1 + dis2 + dis3);
	printf("%.2f", Dis);
	return 0;
}