using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("n=");

        var n=int.Parse(Console.ReadLine());

        double s=0;

        for(int i=1;i<=n;i++){

        Console.Write("a=");

        var a=int.Parse(Console.ReadLine());

        s=s+a;}

        double sr=s/n;

        Console.WriteLine("sr="+Math.Round(sr,2));

    }

}