#!/bin/python

import sys

def minimumNumber(n, password):
    # Return the minimum number of characters to make the password strong
    digit=0
    uppercase=0
    lowercase=0
    special=0
    
    numbers = "0123456789"
    lower_case = "abcdefghijklmnopqrstuvwxyz"
    upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    special_characters = "!@#$%^&*()-+"
    
    for a in range(0,n):
        if (password[a] in numbers):
            digit+=1
        elif (password[a] in lower_case):
            lowercase+=1
        elif (password[a] in upper_case):
            uppercase+=1
        elif (password[a] in special_characters):
            special+=1
    
    req=0
    if digit<1:
        req+=1
    if lowercase<1:
        req+=1
    if uppercase<1:
        req+=1
    if special<1:
        req+=1
    
    length=req+len(password)
    if length<6:
        req=req+(6-length)
    
    return req
            

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