import string


def contains_symbol(word, symbol_string):
    symbols = set(symbol_string)
    if len(word) < len(symbols):
        for letter in word:
            if letter in symbols:
                return True
        return False

    letters = set(word)
    for symbol in symbols:
        if symbol in letters:
            return True
    return False


def minimumNumber(n, password):
    min_chars_to_add = 0
    if not contains_symbol(password, string.ascii_lowercase):
        min_chars_to_add += 1
    if not contains_symbol(password, string.ascii_uppercase):
        min_chars_to_add += 1
    if not contains_symbol(password, string.digits):
        min_chars_to_add += 1
    if not contains_symbol(password, "!@#$%^&*()-+"):
        min_chars_to_add += 1

    min_chars_to_add = max(min_chars_to_add, 6 - n)

    return min_chars_to_add

if __name__ == "__main__":
    n = int(input().strip())
    password = input().strip()
    answer = minimumNumber(n, password)
    print(answer)