#!/bin/python3

import sys

numbers = "0123456789"
lowers = "abcdefghijklmnopqrstuvwxyz"
uppers = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
specials = "!@#$%^&*()-+"

def minimumNumber(n, password):
    needed_for_length = max(0, 6 - len(password))
    needed_for_diversity = 0
    if (not any([(number in password) for number in numbers])):
        needed_for_diversity += 1
    
    if (not any([(lower in password) for lower in lowers])):
        needed_for_diversity += 1
    
    if (not any([(upper in password) for upper in uppers])):
        needed_for_diversity += 1
    
    if (not any([(special in password) for special in specials])):
        needed_for_diversity += 1
    
    return max(needed_for_length, needed_for_diversity)

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