#include<iostream>
#include<cstdio>
#include<cctype>
#include<string>
#include<cmath>
using namespace std;
double dis(int a,int b,int m,int n) {
	return sqrt(pow(a-m,2)+pow(b-n,2));
}
double a,b,c,d,e,f;
int main() {
	cin>>a>>b>>c>>d>>e>>f;
	printf("%.2lf",dis(a,b,c,d)+dis(a,b,e,f)+dis(c,d,e,f));
	return 0;
}