(O.o)/

using namespace std;
int main(){
    double x1,y1,x2,y2,x3,y3;
    cin>>x1>>y1>>x2>>y2>>x3>>y3;
    double ans =sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2))+sqrt((x2-x3)*(x2-x3)+(y2-y3)*(y2-y3))+sqrt((x1-x3)*(x1-x3)+(y1-y3)*(y1-y3));
    cout<<fixed<<setprecision(2)<<ans<<endl;
    return 0;
}