#!/bin/python

import sys

numbers = "0123456789"
lower_case = "abcdefghijklmnopqrstuvwxyz"
upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
special_characters = "!@#$%^&*()-+"

def minimumNumber(n, password):
    # Return the minimum number of characters to make the password strong
    c = 0
    nn = n
    
    if len(set(numbers).difference(password)) == len(numbers):
        c += 1
        nn += 1
    if len(set(lower_case).difference(password)) == len(lower_case):
        c += 1
        nn += 1
    if len(set(upper_case).difference(password)) == len(upper_case):
        c += 1
        nn += 1
    if len(set(special_characters).difference(password)) == len(special_characters):
        c += 1
        nn += 1
        
    if nn < 6:
        c += (6-nn)
        
    return c
        

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