#!/bin/python

import sys

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

def minimumNumber(n, password):
    add = 0
    if len(password) < 6:
        add = max(add, 6-len(password))
    digit = True
    lower = True
    upper = True
    special = True
    for c in password:
        if c in numbers:
            digit = False
        if c in lower_case:
            lower = False
        if c in upper_case:
            upper = False
        if c in special_characters:
            special = False
    needed = digit + lower + upper + special
    add = max(needed, add)
    return add

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