#include <iostream>
#include <cmath>

using namespace std;

double fff(double tab[], int n, double &sa, double &os);

int main()
{
   int n;
   cin >> n;
   double *tab = new double[n];
   for(int i=0;i<n;i++){
    cin >> tab[n];
   }

   double SA=7.7,OS=5.5,SUM;

   SUM = fff(tab,n,SA,OS);
   cout << SUM << endl << SA << endl << OS << endl;
   delete[] tab;
    return 0;
}

double fff(double tab[], int n, double &sa, double &os){
    double s1=0, s2=0;
    for(int i=0;i<n;i++){
        s1+=tab[i];
        s2+=tab[i]*tab[i];
    }
    sa=s1/n;
    os=sqrt((s2/n)*(s2/n)-sa*sa);
    return s1;
}