#!/bin/python3

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

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