#!/bin/python

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 = "!@#$%^&*()-+"

    amount = 0
    has_number = False
    has_lower = False
    has_upper = False
    has_special = False

    for x in password:
        if x in numbers:
            has_number = True
        if x in lower_case:
            has_lower = True
        if x in upper_case:
            has_upper = True
        if x in special_characters:
            has_special = True

    pass_len = len(password) + int(not has_number) + int(not has_lower) + int(not has_upper) + int(not has_special)
    
    #print(pass_len)

    if pass_len < 6:
        amount = 6 - pass_len + (pass_len - len(password))
    else:
        amount = pass_len - len(password)

    return amount

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