$79$
9. Si Si wrote $1, 2, 3, \cdots \cdots, 99$ on the blackboard. Rui Rui doesn't like the number 2, so he erased the following numbers:
(1) multiples of 2;
(2) numbers containing the digit 2 (such as 92);
(3) numbers whose sum of digits is divisible by 2 (such as 31).
Rui Rui erased $\qquad$ numbers in total.