#!/bin/python3

import sys
import string

def minimumNumber(n, password):
    answer = 0
    pass_set = set(password)
    if len(set('!@#$%^&*()-+') & pass_set) == 0:
        answer += 1
    if len(set(string.ascii_lowercase) & pass_set) == 0:
        answer += 1
    if len(set(string.ascii_uppercase) & pass_set) == 0:
        answer += 1
    if len(set(string.digits) & pass_set) == 0:
        answer += 1
    if n < 6:
        temp_answer = 6 - n
        answer = temp_answer if temp_answer > answer else answer
    return answer

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