#!/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 = "!@#$%^&*()-+"
    
    numCharsToAdd = 0
    
    hasNumber = False
    hasLower = False
    hasUpper = False
    hasSpecial = False
    
    
    for char in password:
        
        if char in numbers:
            hasNumber = True
            
        if char in lower_case:
            hasLower = True
        
        if char in upper_case:
            hasUpper = True
            
        if char in special_characters:
            hasSpecial = True
            
        
    if hasNumber is False:
        numCharsToAdd += 1
    
    if hasLower is False:
        numCharsToAdd += 1
        
    if hasUpper is False:
        numCharsToAdd += 1
        
    if hasSpecial is False:
        numCharsToAdd += 1
        
    if (numCharsToAdd + n) < 6:
        numCharsToAdd += 6 - (numCharsToAdd + n)
            
    return numCharsToAdd

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