#!/bin/python

import sys

numbers = "0123456789"
lower_case = "abcdefghijklmnopqrstuvwxyz"
upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
special_characters = "!@#$%^&*()-+"

def has(string, chars):
    for i in range(len(chars)):
        if chars[i] in string:
            return True

def minimumNumber(n, password):
    # Return the minimum number of characters to make the password strong
    min_num = 0
    if n<6:
        min_num = 6-n
    min_addition = 0
    if not has(password, numbers):
        min_addition +=1
    if not has(password, lower_case):
        min_addition +=1
    if not has(password, upper_case):
        min_addition +=1
    if not has(password, special_characters):
        min_addition +=1
    return max(min_addition, min_num)

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