#!/bin/python3

import sys

def minimumNumber(n, password):
    # Return the minimum number of characters to make the password strong
    numbers = set('0123456789')
    lower_case = set('abcdefghijklmnopqrstuvwxyz')
    upper_case = set('ABCDEFGHIJKLMNOPQRSTUVWXYZ')
    special_characters = set('!@#$%^&*()-+')

    extra_count = 0
    if not numbers.intersection(password):
        extra_count += 1
    if not lower_case.intersection(password):
        extra_count += 1
    if not upper_case.intersection(password):
        extra_count += 1
    if not special_characters.intersection(password):
        extra_count += 1
    return max(extra_count, 6-n)
    

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