Yi and sue play a game. they start with the number $42000$. yi divides by a prime number, then passes the quotient to sue. then sue divides this quotient by a prime number and passes the result back to yi, and they continue taking turns in this way. for example, yi could start by dividing $42000$ by $3$. in this case, he would pass sue the number $14000$. then sue could divide by $7$ and pass yi the number $2000$, and so on. the players are not allowed to produce a quotient that isn't an integer. eventually, someone is forced to produce a quotient of $1$, and that player loses. for example, if a player receives the number $3$, then the only prime number (s)he can possibly divide by is $3$, and this forces that player to lose. who must win this game, and why?