#!/bin/python3

import sys

def minimumNumber(n, password):
	# Return the minimum number of characters to make the password strong
	numbers = "0123456789"
	lower_case = "abcdefghijklmnopqrstuvwxyz"
	upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
	special_characters = "!@#$%^&*()-+"
	
	has_numbers = 1
	has_lower_case = 1
	has_upper_case = 1
	has_special_characters = 1
	
	for i in password:
		if i in numbers:
			has_numbers = 0
		elif i in lower_case:
			has_lower_case = 0
		elif i in upper_case:
			has_upper_case = 0
		elif i in special_characters:
			has_special_characters = 0
			
		if has_numbers == 0 and has_lower_case == 0 and has_upper_case == 0 and has_special_characters == 0:
			break
	
	sum = has_special_characters + has_lower_case + has_upper_case + has_numbers
	return max(6-n , sum)

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