#!/bin/python3

import sys
import re

def minimumNumber(n, password):
    # Return the minimum number of characters to make the password strong
    res = 0
    if not re.search("\\d", password):
        res += 1
    if not re.search("[a-z]", password):
        res += 1
    if not re.search("[A-Z]", password):
        res += 1
    if not re.search("\\W", password):
        res += 1
    return res + max(0, 6-len(password)-res) 

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