using System;
public class Program
{
public static void Main()
int a,q=0;
double p=0;
string s;
do {
Console.Write("a=");
s=Console.ReadLine();
a=Convert.ToInt32(s);
p+=a;
q++;
}
while (a!=0);
p=p/(q-1);
Console.WriteLine("p="+p);