#!/bin/python3

import sys

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

def minimumNumber(n, password):
    digit, lower, upper, spec = [False] * 4
    for c in password:
        if c in numbers:
            digit = True
        elif c in lower_case:
            lower = True
        elif c in upper_case:
            upper = True
        elif c in special_characters:
            spec = True
            
    flag = (0 if digit else 1) + (0 if lower else 1) + (0 if upper else 1) + (0 if spec else 1)
    res = 6 - n
    return res if res - flag >= 0 else flag

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