#!/bin/python3

import sys

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

def minimumNumber(n, password):     
    if n <= 3:
        return 6 - n    
    nums = 1 
    lows = 1
    ups = 1
    sp = 1
    
    for c in password: 
        if c in numbers and nums > 0: 
            nums -= 1
        elif c in lower_case and lows > 0: 
            lows -= 1
        if c in upper_case and ups > 0: 
            ups -= 1
        if c in special_characters and sp > 0: 
            sp -= 1 
    total_missing = nums + lows + ups + sp 
    return max(total_missing, 6 - n)
    #return (6 - n) + (total_missing - (6 - n)) if n < 6 else total_missing

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