include<bits/stdc++.h> using namespace std; int jv(double a,double b,double c,double d) {

if(abs(a)<100||abs(a)==100&&abs(b)<100||abs(b)==100&&abs(c)<100||abs(c)==100&&abs(d)<100||abs(d)==100)
{
   
	return  sqrt(((a-c)*(a-c)*1.00+(b-d)*(b-d)*1.00)/0.1/10);
}

} int main() { double a,b,c,d,e,f,zhou; cin>>a>>b>>c>>d>>e>>f; zhou=(jv(a,b,c,d)+jv(a,b,e,f)+jv(c,d,e,f))*1.00; cout<<fixed<<setprecision(2)<<zhou; }