numbers = "0123456789"
lower_case = "abcdefghijklmnopqrstuvwxyz"
upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
special_characters = "!@#$%^&*()-+"
n = int(input())
s=input()
a=0;b=0;c=0;d=0
for i in s:
    if(a==0 and i in numbers):
        a=1
    elif(b==0 and i in lower_case):
        b=1
    elif(c==0 and i in upper_case):
        c=1
    elif(d==0 and i in special_characters):
        d=1
a=[a,b,c,d]
count=0
for i in a:
    if(i==0):
        count+=1
if(n+count<6):
    print(6-n)
else:
    print(count)