#include<stdio.h>
#include<math.h>
#define PRINTF "%lf %lf"
double C(double x1,double x2,double y1,double y2)
{
	double sum;
	sum=sqrt(pow((x2-x1),2)+pow((y2-y1),2));
	return sum;
}
int main()
{
	double x1,x2,x3,y1,y2,y3,sum,c1,c2,c3;
	scanf(PRINTF,&x1,&y1);
	scanf(PRINTF,&x2,&y2);
	scanf(PRINTF,&x3,&y3);
	c1=C(x1,x2,y1,y2);
	c2=C(x2,x3,y2,y3);
	c3=C(x3,x1,y3,y1);
	sum=c1+c2+c3;
	printf("%.2lf",sum);
	return 0;
}