using System;

public class Program

{

    public static void Main()

    {

            int cur = Convert.ToInt32(Console.ReadLine());

            int sum = 0;

            int qty = 0; // qty = quantity, прост немношк)

​

            while (cur != 0)

            {

                qty++;

                sum += cur;

                cur = Convert.ToInt32(Console.ReadLine());

            }

            Console.WriteLine(sum / qty);

    }

}