using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;
namespace Rextester
{
public class Program
{
public static void Main(string[] args)
{
int [] arr = new int[5];
float sum = 0;
for (int i = 0; i < 5; i++) {
arr[i] = int.Parse(Console.ReadLine());
sum += arr[i];
}
Console.WriteLine(sum/5);
}
}
}