numbers = "0123456789"
lower_case = "abcdefghijklmnopqrstuvwxyz"
upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
special_characters = "!@#$%^&*()-+"
n=int(input())
a=input()
f=[0]*4
ans=0
for i in a:
    if(i in numbers):
        f[0]=1
    elif(i in lower_case):
        f[1]=1
    elif(i in upper_case):
        f[2]=1
    elif(i in special_characters):
        f[3]=1
print(max(6-len(a),4-sum(f)))