#!/bin/python

import sys

def minimumNumber(n, password):
    s = password
    num_chars = 0
    numbers = "0123456789"
    lower_case = "abcdefghijklmnopqrstuvwxyz"
    upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    special_characters = "!@#$%^&*()-+"
    for v in [numbers, lower_case, upper_case, special_characters]:
        if not any([n in s for n in v]):
            num_chars += 1
    if len(s) + num_chars < 6:
        num_chars += 6 - len(s) - num_chars
    return num_chars

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