#!/bin/python3

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
    nu=lc=uc=sc=False
    for p in password:
        nu|=p in numbers
        lc|=p in lower_case
        uc|=p in upper_case
        sc|=p in special_characters
    to_add = 4-nu-lc-uc-sc
    if to_add+n<6: to_add=6-n
    return to_add
    

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