numbers = "0123456789"
lower_case = "abcdefghijklmnopqrstuvwxyz"
upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
special_characters = "!@#$%^&*()-+"

n = int(input())
s = input()

bn,bl,bu,bs = False,False,False,False

for c in s:
	if c in numbers:
		bn = True
	if c in lower_case:
		bl = True
	if c in upper_case:
		bu = True
	if c in special_characters:
		bs = True
res = 0
if not bn:
	res += 1
if not bl:
	res += 1
if not bu:
	res += 1
if not bs:
	res += 1

if len(s) < 6:
	res = max(res, 6-len(s))
print(res)