#include<bits/stdc++.h>
using namespace std;
double ch(int a,int b,int c,int d){
	double ret=sqrt(abs((a-c)*(a-c))+abs((b-d)*(b-d)));
	return ret;
}
int main(){
	int a,b,c,d,e,f;
	cin>>a>>b>>c>>d>>e>>f;
	double ret=ch(a,b,c,d)+ch(a,b,e,f)+ch(c,d,e,f);
	printf("%.2f",ret);
 }