#include <iostream>
#include <cmath>
using namespace std;
float ld(float x1,float x2,float y1,float y2)
{
	float num;
	num=((x1-x2)*(x1-x2))+((y1-y2)*(y1-y2));
	num=sqrt(num);
	return num;
}
int main()
{
	float x1,x2,y1,y2,z1,z2,sum;
	cin>>x1>>x2>>y1>>y2>>z1>>z2;
	sum=ld(x1,x2,y1,y2)+ld(y1,y2,z1,z2)+ld(x1,x2,z1,z2);
	printf("%.2f",sum);
	return 0;
}