import string
n = int(input())
pas = input()
spec = '!@#$%^&*()-+'
missing = [1,1,1,1]
for c in pas:
    if c in string.ascii_lowercase:
        missing[0]=0
    if c in string.ascii_uppercase:
        missing[1]=0
    if c in spec:
        missing[2]=0
    if c in '0123456789':
        missing[3]=0
print(max(0,max(6-n, sum(missing))))