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

q = "0123456789"
l = "abcdefghijklmnopqrstuvwxyz"
u = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
w = "!@#$%^&*()-+"

a = 0
b = 0
c = 0
d = 0

for x in s:
    if x in q:
        a+=1
    elif x in l:
        b += 1
    elif x in u:
        c += 1
    elif x in w:
        d += 1

print(max(6 - n, int(a == 0) + int(b == 0) + int(c == 0) + int(d == 0)))