numbers = "0123456789"
lower_case = "abcdefghijklmnopqrstuvwxyz"
upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
special_characters = "!@#$%^&*()-+"
flag1=flag2=flag3=flag4=count=0
n = int(input())
string = input()
for i in range(n):
    if string[i] in numbers:
        flag1=1
    elif string[i] in lower_case:
        flag2=1
    elif string[i] in upper_case:
        flag3=1
    elif string[i] in special_characters:
        flag4=1
if flag1==0:
    count+=1
if flag2==0:
    count+=1
if flag3==0:
    count+=1
if flag4==0:
    count+=1
if n<6:
    print(max(count,6-n))
if n>=6:
    print(count)