#!/bin/python3

import sys
from string import punctuation

def minimumNumber(n, password):
    # Return the minimum number of characters to make the password strong
    min_chars = 4
    if any(c.isdigit() for c in password):
        min_chars -= 1
    if any(c.islower() for c in password):
        min_chars -= 1
    if any(c.isupper() for c in password):
        min_chars -= 1
    special_chars = set(c for c in "!@#$%^&*()-+")
    if any(c in special_chars for c in password):
        min_chars -= 1
    return max(min_chars, 6 - len(password))
    

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