#!/bin/python3

import sys

def minimumNumber(n, password):
  numbers = "0123456789"
  lower_case = "abcdefghijklmnopqrstuvwxyz"
  upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
  special_characters = "!@#$%^&*()-+"
  hasnumber = False
  for i in numbers:
    if i in password:
      hasnumber = True
      break
  haslc =False
  for i in lower_case:
    if i in password:
      haslc = True
      break
  hasuc = False
  for i in upper_case:
    if i in password:
      hasuc = True
      break
  hassc = False
  for i in special_characters:
    if i in password:
      hassc = True
      break
  need_more = 0
  if not hasnumber :
    need_more +=1 
  if not haslc :
    need_more +=1 
  if not hasuc :
    need_more +=1 
  if not hassc :
    need_more +=1 
  l = 6 - len(password) 
  if l == need_more:
    return need_more
  elif l > need_more:
    return l
  else:
    return need_more
  
    

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