using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("m1");

        int x = int.Parse(Console.ReadLine());

        Console.WriteLine("m2");

        int y = int.Parse(Console.ReadLine());

        Console.WriteLine("m3");

        int s = int.Parse(Console.ReadLine());

        int average = (x + y + s) / 3;

        Console.Write(average);

    }

}