#!/bin/python3

import sys

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

def containsDigit(password):
    for c in password:
        if c in list(numbers):
            return True
    return False

def containsLower(password):
    for c in password:
        if c in list(lower_case):
            return True
    return False

def contaisHigher(password):
    for c in password:
        if c in list(upper_case):
            return True
    return False

def containsSpecial(password):
    for c in password:
        if c in list(special_characters):
            return True
    return False

def minimumNumber(n, password):
    add = 0
    if not containsDigit(password):
        add += 1
    if not containsLower(password):
        add += 1
    if not contaisHigher(password):
        add += 1
    if not containsSpecial(password):
        add += 1
        
    rem = 6-n
    if add > rem:
        return add
    return rem
    
if __name__ == "__main__":
    n = int(input().strip())
    password = input().strip()
    answer = minimumNumber(n, password)
    print(answer)