numbers = "0123456789"
lower_case = "abcdefghijklmnopqrstuvwxyz"
upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
special_characters = "!@#$%^&*()-+"
n = input()
st = raw_input().strip()
needed = 0
f1,f2,f3,f4 = 0,0,0,0
for i in st:
    # if(f1==0 or f2==0 or f3 == 0 or f4 == 0):
    if i in numbers:
        f1= 1
    if i in lower_case:
        f2 = 1
    if i in upper_case:
        f3 = 1
    if i in special_characters:
        f4 = 1
ned = 4 - f1-f2-f3-f4
# print f1,f2,f3,f4
if(n + ned<6):
    print ned + (6-n-ned)
else:
    print ned