#!/bin/python

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

def minimumNumber(password):
    # Return the minimum number of characters to make the password strong
    need = 0
    if not any(map(lambda x: x in numbers, password)):
      need += 1
    if not any(map(lambda x: x in lower_case, password)):
      need += 1
    if not any(map(lambda x: x in upper_case, password)):
      need += 1
    if not any(map(lambda x: x in special_characters, password)):
      need += 1
    if len(password) + need < 6:
      return 6 - len(password)
    return need
    
if __name__ == "__main__":
    n = int(raw_input().strip())
    password = raw_input().strip()
    answer = minimumNumber( password)
    print answer