#!/bin/python3

import sys

numbers = "0123456789"
lower_case = "abcdefghijklmnopqrstuvwxyz"
upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
special_characters = "!@#$%^&*()-+"


def minimumNumber(n, password):
    # if n < 6:
    #     return 6 - n
    if (any(x in lower_case for x in password) and any(x in upper_case for x in password)
        and any(x.isdigit() for x in password) and any(x in special_characters for x in password) and n >= 6):
        return 0
    counter = 4
    counter -= any(x in lower_case for x in password)
    counter -= any(x in upper_case for x in password)
    counter -= any(x in numbers for x in password)
    counter -= any(x in special_characters for x in password)

    if n >= 6:
        return counter
    else:
        return (6 - n) if (6 - n) >= counter else counter

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