using System.Collections.Generic;
using System.Threading.Tasks;
public static void Main(string[] args)
string number = Console.ReadLine();
int[] digits = number.Select(i => int.Parse(i.ToString(), System.Globalization.NumberStyles.HexNumber)).ToArray();
int initialLastDigit = digits.Last();
bool haveZeros = digits.Any(d => d == 0);
result = (double)digits.Select(i => i % 5).Sum() / digits.Length;
List<int> remainders = new List<int>();
for (int index = 0; index < digits.Length; index++)
int[] remainDigits = digits.Take(index).Union(digits.Skip(index + 1)).ToArray();
if (!remainDigits.Any(i => i == 0))
remainders.Add((digits.Length - 1) * (digits[index] % 5));
remainders.Add(initialLastDigit % 5);
remainders.Add((digits.Length - 2) * (digits[index] % 5));
result = (double)remainders.Sum() / (digits.Length * (digits.Length - 1));
Console.WriteLine(Math.Round(result, 9));