#!/bin/python

import sys

def minimumNumber(n, password):
    # Return the minimum number of characters to make the password strong
    numbers = list("0123456789")
    lower_case = list("abcdefghijklmnopqrstuvwxyz")
    upper_case = list("ABCDEFGHIJKLMNOPQRSTUVWXYZ")
    special_characters = list("!@#$%^&*()-+")
    num = 0
    lower = 0
    upper = 0
    special = 0
    for e in password:
        if e in numbers:
            num+=1
        elif e in lower_case:
            lower+=1
        elif e in upper_case:
            upper+=1
        elif e in special_characters:
            special+=1
    toadd = 0
    if num==0:
        toadd+=1
    if lower==0:
        toadd+=1
    if upper==0:
        toadd+=1
    if special==0:
        toadd+=1
    if n+toadd<6:
        toadd = 6-n
    
    return toadd

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