#!/bin/ruby


def minimumNumber(n, password)
    numbers = "0123456789"
    lower_case = "abcdefghijklmnopqrstuvwxyz"
    upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    special_characters = "!@\#$%^&*()-+"
    special_characters_arr = special_characters.split('')
    # Return the minimum number of characters to make the password strong
    has_six = n >= 6
    has_number = numbers.split('').any? { |word| password.include?(word) }
    has_lower = lower_case.split('').any? { |word| password.include?(word) }
    has_upper = upper_case.split('').any? { |word| password.include?(word) }
    has_special = special_characters.split('').any? { |word| password.include?(word) }
    #puts has_six, has_number, has_lower, has_upper, has_special
    after = [has_number, has_lower, has_upper, has_special].count{|t| !t }
    #puts after
    if has_six
        after
    else
        n + after >= 6 ? after : (after + (6 - n - after))
    end
end

n = gets.strip.to_i
password = gets.strip
answer = minimumNumber(n, password)
puts answer