#!/bin/python

import sys

def minimumNumber(n, password):
    numbers = "0123456789"
    lower_case = "abcdefghijklmnopqrstuvwxyz"
    upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    special_characters = "!@#$%^&*()-+"
    needed = 0
    if(not(any(elem in numbers for elem in password))):
        needed += 1
    if (not (any(elem in lower_case for elem in password))):
        needed += 1
    if (not (any(elem in upper_case for elem in password))):
        needed += 1
    if (not (any(elem in special_characters for elem in password))):
        needed += 1
    if(n+needed < 6):
        needed = 6 - n
    return needed

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