#!/bin/python3

import sys

def minimumNumber(n, password):
    toadd = 0 #minimum characters to add
    digits = 0
    length = 0
    lowercase = 0
    uppercase = 0
    specialChars = 0
    characters = ['!','@','#','$','%','^','&','*','(',')','-','+']
    # Return the minimum number of characters to make the password strong
    
    for char in password:
        #check for special characters
        if char in characters:
            specialChars += 1
        elif char.isdigit():
            digits += 1
        #check case case, istitle()
        elif char.isupper():
            uppercase += 1
        elif char.islower():
            lowercase += 1
            
    #get neede characters
    if specialChars < 1:
        toadd += 1
            
    if lowercase < 1:
        toadd += 1
        
    if uppercase < 1:
        toadd += 1
        
    if digits < 1:
        toadd += 1
        
        
    if len(password) >= 6:
        return toadd
    
    else:
        if len(password) + toadd >= 6:
            return toadd
        elif toadd == 0 and len(password) < 6:
            return 6 - len(password)
        elif toadd < (6 - len(password)):
            return (6 - len(password))
        else:
            return toadd + (6 - len(password))
    
        
    

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