#include <iostream>
#include <iomanip>
#include <vector>
#include <math.h>

using namespace std;

class Poligon{
private:
    vector<double> x;
    vector<double> y;
    int n;
public:
    void setPoligon(int m,vector<double>p,vector<double>q){
        n=m;x=p;y=q;
    }
    void print(){
        cout << "[" << fixed << setprecision(2) << x[0] << "," << y[0] << "]" << "-" << "[" << x[n-1] << "," << y[n-1] << "]" << endl;
        cout << fixed << setprecision(2) << keliling() << endl;
    }
    double keliling(){
        double Kx,Ky,Kl,K=0;
        for(int i=0;i<n-1;i++){
            Kx=(x[i]-x[i+1])*(x[i]-x[i+1]);
            Ky=(y[i]-y[i+1])*(y[i]-y[i+1]);
            K+=sqrt(Kx+Ky);
        }
        Kl=sqrt(((x[0]-x[n-1])*(x[0]-x[n-1])) + ((y[0]-y[n-1])*(y[0]-y[n-1])));
        K=(K+Kl);
        return K;
    }
};

int main (){
    int n;
    cin >> n;
    vector<double> vx;
    vector<double> vy;
    Poligon g;
    double x,y;
    for(int i=0;i<n;i++){
        cin >> x >> y;
        vx.push_back(x);
        vy.push_back(y);
        g.setPoligon(n,vx,vy);
    }
    g.print();
    return 0;
}