#!/bin/python3

import sys

def minimumNumber(n, password):
    numbers = "0123456789"
    lower_case = "abcdefghijklmnopqrstuvwxyz"
    upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    special_characters = "!@#$%^&*()-+"
    # Return the minimum number of characters to make the password strong
    fl_digit, fl_lower, fl_upper, fl_spe = [0, 0, 0, 0]
    len_pass = len(password)
    for i in range(len_pass):
        unit = password[i]
        if unit in numbers:
            fl_digit = 1
        elif unit in lower_case:
            fl_lower = 1
        elif unit in upper_case:
            fl_upper = 1
        elif unit in special_characters:
            fl_spe = 1
    add = 4 - fl_digit - fl_lower - fl_upper - fl_spe
    if len_pass + add < 6:
        return 6 - len_pass
    else:
        return add

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