Question 85
Someone has written the numbers $1$, $2$, $\ldots$, $33$ on a chalkboard. In each step, we choose two (not necessarily different) numbers on the chalkboard such that one divides the other. We then erase these two numbers and write their quotient, which is a natural number, on the chalkboard. We repeat the process until there is a pair of numbers on the chalkboard such that one of the numbers divides the other. At least how many numbers stay written on the chalkboard?