#!/bin/python3

import sys

def minimumNumber(n, password):
    # Return the minimum number of characters to make the password strong
    length = len(password)
    
    numbers = "0123456789"
    lower_case = "abcdefghijklmnopqrstuvwxyz"
    upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    special_characters = "!@#$%^&*()-+"
    
    count, change, numbers_count, lcase_count, ucase_count, spcase_count = 0, 0, 0, 0, 0, 0
    
    for ch in password:
        if ch in numbers:
            numbers_count += 1
        elif ch in lower_case:
            lcase_count += 1
        elif ch in upper_case:
            ucase_count += 1
        elif ch in special_characters:
            spcase_count += 1
            
            
    if numbers_count == 0:
        numbers_count += 1
        change += 1
        
    if lcase_count == 0:
        lcase_count += 1
        change += 1
        
    if ucase_count == 0:
        ucase_count += 1
        change += 1
        
    if spcase_count == 0:
        spcase_count += 1
        change += 1
    
    count = numbers_count + lcase_count + ucase_count + spcase_count
    if count < 6:
        return change + 6 - count
    else:
        return change
        
        
           

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