#!/bin/python3

import sys

def minimumNumber(n, password):
    # Return the minimum number of characters to make the password strong
    flag_digit = False
    flag_lower = False
    flag_upper = False
    flag_special = False
    for c in password:
        if c in "0123456789":
            flag_digit = True
        elif c in "abcdefghijklmnopqrstuvwxyz":
            flag_lower = True
        elif c in "ABCDEFGHIJKLMNOPQRSTUVWXYZ":
            flag_upper = True
        elif c in "!@#$%^&*()-+":
            flag_special = True
    reqs = [flag_digit, flag_lower, flag_upper, flag_special].count(False)
    return max(max(6-n, 0), reqs)


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