#!/bin/python3

import sys

def minimumNumber(n, password):
    # Return the minimum number of characters to make the password strong
    needed = 0
    upper, lower, digit, special = False, False, False, False
    spec = ['!', '@', '#', '$', '%', '^', '&', '*', '(', ')', '-', '+']
    for c in password:
        if c.isupper():
            upper = True
        elif c.islower():
            lower = True
        elif c.isdigit():
            digit = True
        elif c in spec:
            special = True
    if upper == False:
        needed += 1
    if lower == False:
        needed += 1
    if digit == False:
        needed += 1
    if special == False:
        needed += 1
    if 6 - len(password) > needed:
        return 6 - len(password)
    return needed

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