#!/bin/ruby

def minimumNumber(n, password)
  numbers = "0123456789"
  lower_case = "abcdefghijklmnopqrstuvwxyz"
  upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
  special_characters = "!@#$%^&*()-+"
  
  has_num = false
  has_lower = false
  has_upper = false
  has_spec = false
  for i in (0..n - 1)
    if (numbers.index(password[i]))
      has_num = true
    end
    if (lower_case.index(password[i]))
      has_lower = true
    end
    if (upper_case.index(password[i]))
      has_upper = true
    end
    if (special_characters.index(password[i]))
      has_spec = true
    end
  end
  needed = 0
  needed += 1 if !has_num
  needed += 1 if !has_lower
  needed += 1 if !has_upper
  needed += 1 if !has_spec
  if n + needed >= 6
    return needed
  else
    return 6 - n
  end
end

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