#!/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 = "!@#$%^&*()-+"
    chars_to_add = 0
    
    chars = {
        'number':0,
        'lower_case':0,
        'upper_case':0,
        'special_characters':0
    }
    for ch in password:
        if ch in numbers:
            chars['number'] += 1
        if ch in lower_case:
            chars['lower_case'] += 1
        if ch in upper_case:
            chars['upper_case'] += 1
        if ch in special_characters:
            chars['special_characters'] += 1

        if dict_full(chars):
            break
    
    result = count_empty(chars) 
    if (result + n) < 6:
        return 6 - n
    else:
        return result
    
    
def dict_full(c):
    return c['number'] > 0 and c['lower_case'] > 0 and c['upper_case'] > 0 and c['special_characters'] > 0
        
def count_empty(c):
    result = 0
    for key, value in c.items():
        if value == 0:
            result += 1
    return result        
            
if __name__ == "__main__":
    n = int(input().strip())
    password = input().strip()
    answer = minimumNumber(n, password)
    print(answer)