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);
}