#!/bin/python3

import sys

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

def minimumNumber(n, p):
    # Return the minimum number of characters to make the password strong
    s = 0
    s += not any(c in lower_case for c in p)
    s += not any(c in upper_case for c in p)
    s += not any(c in special_characters for c in p)
    s += not any(c in numbers for c in p)
    if s +n>=6:
        return s
    else:
        return 6-n

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