#!/bin/python3

import sys

def minimumNumber(n, password):
	num = list ('0123456789')
	small = list ('abcdefghijklmnopqrstuvwxyz')
	large = list('ABCDEFGHIJKLMNOPQRSTUVWXYZ')
	# print (small)
	sp = list ('!@#$%^&*()-+')
	a = b = c = d = 0
	for i in range (0,n):
		if password[i] in num:
			a = 1
		if password[i] in small:
			b = 1
		if password[i] in large:
			c = 1
		if password[i] in sp:
			d = 1

	cnt = 4-(a+b+c+d)
	if cnt+n < 6:
		return 6-n
	else:
		return cnt 


n = int(input().strip())
password = input().strip()
answer = minimumNumber(n, password)
print(answer)