#include<bits/stdc++.h> 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; }

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;
}

(O.o)/