t=int(input())
s=input()
s=[i for i in s]
numbers = "0123456789"
lower_case = "abcdefghijklmnopqrstuvwxyz"
upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
special_characters = "!@#$%^&*()-+"
c=0
if not any(i in s for i in numbers):
    c+=1
if not any(i in s for i in lower_case):
    c+=1
if not any(i in s for i in upper_case):
    c+=1
if not any(i in s for i in special_characters):
    c+=1
print(6-(len(s)) if c <6-len(s) else c)