#!/bin/python

import sys

def minimumNumber(n, password):
    pwd  = set(password)
    num = len(set("0123456789")&pwd)
    lower_case = len(set("abcdefghijklmnopqrstuvwxyz")&pwd)
    upper_case = len(set("ABCDEFGHIJKLMNOPQRSTUVWXYZ")&pwd)
    special_characters = len(set("!@#$%^&*()-+")&pwd)
    res = 0
    if num==0:
        res+=1
    if lower_case==0:
        res+=1
    if upper_case==0:
        res+=1
    if special_characters==0:
        res+=1
    if n>=6:
        return res
    else:
        return max(res, 6-n)

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