#!/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
    leng = True
    digit = True
    lower = True
    upper = True
    special = True
    if n < 6:
        leng = False
    if not any([1 for x in password if x in numbers]):
        digit = False
    if not any([1 for x in password if x in lower_case]):
        lower = False
    if not any([1 for x in password if x in upper_case]):
        upper = False
    if not any([1 for x in password if x in special_characters]):
        special = False
    if leng:
        nec = sum([1 for x in [digit, lower, upper, special] if not x])
        return nec
    else:
        nec = sum([1 for x in [digit, lower, upper, special] if not x])
        if not nec+n >= 6:
            return nec + (6-(nec+n))
        return nec
if __name__ == "__main__":
    n = int(raw_input().strip())
    password = raw_input().strip()
    answer = minimumNumber(n, password)
    print answer