#!/bin/python

import sys
numbers = "0123456789"
lower_case = "abcdefghijklmnopqrstuvwxyz"
upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
special_characters = "!@#$%^&*()-+"
def minimumNumber(n, password):
    a=[0,0,0,0]
    # Return the minimum number of characters to make the password strong
    for i in password:
        if i in numbers:
            a[0]+=1
        else:
            if i in lower_case:
                a[1]+=1
            else:
                if i in upper_case:
                    a[2]+=1
                else:
                    if i in special_characters:
                        a[3]+=1
    c=0
    for i in a:
        if i==0:
            c+=1
            n+=1
    if n<6:
        c+=6-n
    return c

if __name__ == "__main__":
    n = int(raw_input().strip())
    password = raw_input().strip()
    answer = minimumNumber(n, password)
    print answer