#include <bits/stdc++.h>
using namespace std;
int dis(){
	float a,b,c,d,e,f;
	float m,n,p,q;
	cin>>a>>b;
	cin>>c>>d;
	cin>>e>>f;
	m = sqrt((e - a) * (e - a) + (f - b) * (f - b));
	n = sqrt((c - a) * (c - a) + (d - b) * (d - b));
	p = sqrt((e - c) * (e - c) + (f - d) * (f - d));
	q = float(m + n + p);
	printf("%.2f", q);
}
int main(){
	dis();
	return 0;
}