#!/bin/python3

import sys

def minimumNumber(n, password):
    numbers = "0123456789"
    lower_case = "abcdefghijklmnopqrstuvwxyz"
    upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    special_characters = "!@#$%^&*()-+"
    
    
    
    s = [False,False,False,False]
    characters = 0
    
    for i in range(n):
        if password[i] in numbers:
            s[0] = True
        if password[i] in lower_case:
            s[1] = True
        if password[i] in upper_case:
            s[2] = True
        if password[i] in special_characters:
            s[3] = True
    
    for i in s:
        if i == False:
            characters +=1
    while characters + n < 6:
        characters +=1
    return characters
    
        

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