#!/bin/python3

import sys

def minimumNumber(n, password):
    numbers = "0123456789"
    lower_case = "abcdefghijklmnopqrstuvwxyz"
    upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    special_characters = "!@#$%^&*()-+"
    
    a = any(l in password for l in lower_case)
    b = any(l in password for l in upper_case)
    c = any(l in password for l in special_characters)
    d = any(l in password for l in numbers)
    
    cond = sum((a,b,c,d))
    toadd1 = 4-cond
    toadd2 = max(0, 6-len(password))
    return max(toadd1, toadd2)

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