#!/bin/python3

import sys

def minimumNumber(n, password):
    # Return the minimum number of characters to make the password strong
    numbers = "0123456789"
    lower_case = "abcdefghijklmnopqrstuvwxyz"
    upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    special_characters = "!@#$%^&*()-+"
    count = 0
    for i in numbers:
        if i in password:
            count += 1
            break
    for i in lower_case:
        if i in password:
            count += 1
            break
    for i in upper_case:
        if i in password:
            count += 1
            break
    for i in special_characters:
        if i in password:
            count += 1
            break
    if count == 4:
        return max(6-n,0)
    elif n>=6:
        return 4-count
    else:
        totalcount = n + 4-count
        return max(6-totalcount,0) + 4-count

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