#!/bin/python3

import sys


def minimumNumber(n, password):
    has_number = 0
    has_low = 0
    has_upper = 0
    has_special = 0
    for c in range(0,n):
        char = password[c]
        if (has_number < 1 and char <= '9' and char >= '0'):
            has_number = 1
        if (has_low < 1 and char <= 'z' and char >= 'a'):
            has_low = 1
        if (has_upper < 1 and char <= 'Z' and char >= 'A'):
            has_upper = 1
        if (has_special < 1 and char in "!@#$%^&*()-+"):
            has_special = 1
            
    boxes_checked = has_number + has_low + has_upper + has_special
    missing_char_types = 4 - boxes_checked
    chars_needed = missing_char_types
    length_after_missing_types_added = n + chars_needed
    if (length_after_missing_types_added < 6):
        chars_needed += 6 - length_after_missing_types_added
         
    return chars_needed

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