#!/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 = "!@#$%^&*()-+"
    min_num = 0
    
    missing_num = 1
    missing_lower = 1
    missing_upper = 1
    missing_special = 1
    
    for c in password:
        if c in numbers:
            missing_num = 0
        if c in lower_case:
            missing_lower = 0
        if c in upper_case:
            missing_upper = 0
        if c in special_characters:
            missing_special = 0
    
    min_num = 6-n
    missing_chars = missing_num + missing_lower + missing_upper + missing_special
    return min_num if min_num > missing_chars else missing_chars

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