Call a positive integer monotonous in base 8 if it is a one-digit number in base 8 or its base 8 digits when read from left to right form either a strictly increasing or a strictly decreasing sequence. For example, $3_8$, $2357_8$, and $76520_8$ are monotonous in base 8, but $44_8$, $7434_8$, and $23557_8$ are not. How many monotonous positive integers are there in base 8?