#!/bin/python3

import sys

def minimumNumber(n, password):
    numbers = list("0123456789")
    lower_case = list("abcdefghijklmnopqrstuvwxyz")
    upper_case = list("ABCDEFGHIJKLMNOPQRSTUVWXYZ")
    special_characters = list("!@#$%^&*()-+")
    # Return the minimum number of characters to make the password strong
    lower = False
    upper = False
    number = False
    special = False
    for c in password:
        if(not number and c in numbers):
            number = True
        elif(not lower and c in lower_case):
            lower = True
        elif(not upper and c in upper_case):
            upper = True
        elif(not special and c in special_characters):
            special = True
    count = 0
    if(not number):
        count += 1
    if(not lower):
        count += 1
    if(not upper):
        count += 1
    if(not special):
        count += 1
    return (max(count, 6 - n))

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