#include <cmath>
#include <iostream>
#include <cstdio>
using namespace std;
double a,b,c,d,e,f;
double dit(double a,double b,double c,double d){
	double ans;
	ans=sqrt(pow((a-c),2)+pow(b-d,2));
	ans=((ans>0)?ans:ans*-1);
	return ans;
}
int main(){
	cin>>a>>b>>c>>d>>e>>f;
	cout<<dit(a,b,c,d)+dit(a,b,e,f)+dit(c,d,e,f);
	return 0;
}