You and a friend take turns saying positive integers greater than one. You can't say a number that is a multiple of previous numbers or a sum of multiples of previous numbers. For example, if A says 3 and B says 7 then A cannot say 17, because 17=2*7+3. If you are unable to say a number you lose.
One way to lose is by starting off saying the number 2 or 3; then the other person says the one you didn't say and when it comes back to your turn you lose (2 and 3 can make any positive integer greater than 1).
What are some strategies, how do you win?