#!/bin/python3

import sys

def minimumNumber(n, password):
    num = False
    low = False
    upp = False
    sym = False
    numbers = "0123456789"
    lower_case = "abcdefghijklmnopqrstuvwxyz"
    upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    special_characters = "!@#$%^&*()-+"
    for c in password:
        if c in numbers:
            num = True
        elif c in lower_case:
            low = True
        elif c in upper_case:
            upp = True
        elif c in special_characters:
            sym = True
    count = 0
    if not num:
        count += 1
    if not low:
        count += 1
    if not upp:
        count += 1
    if not sym:
        count += 1
    return(max(count,6-n))

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