#!/bin/python3

import sys

def minimumNumber(n, password):
    # Return the minimum number of characters to make the password strong
    numbers = "0123456789"
    lower_case = "abcdefghijklmnopqrstuvwxyz"
    upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    special_characters = "!@#$%^&*()-+"
    digit, lowercase, uppercase, special = 1, 1, 1, 1
    for i in range(n):
        if password[i] in lower_case:
            lowercase = 0
        elif password[i] in upper_case:
            uppercase = 0
        elif password[i] in numbers:
            digit = 0
        elif password[i] in special_characters:
            special = 0
    if n < 6:
        return max(6 - n, lowercase + uppercase + digit + special) 
    else:
        return lowercase + uppercase + digit + special   
if __name__ == "__main__":
    n = int(input().strip())
    password = input().strip()
    answer = minimumNumber(n, password)
    print(answer)