#!/bin/python3

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

def minimumNumber(n, password):
    nu = sum(i in numbers for i in password)
    lo = sum(i in lower_case for i in password)
    up = sum(i in upper_case for i in password)
    sp = sum(i in special_characters for i in password)
    k = (nu==0) + (lo==0) + (up == 0) + (sp==0)
    return max(k, 6-n)
    

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