Alex has invented a new game for fun. There are $n$ integers at a board and he performs the following moves repeatedly:
1. He chooses three numbers $a$, $b$ and $c$ written at the board and erases them.
2. He chooses two numbers from the triple $a$, $b$ and $c$ and calculates their greatest common divisor, getting the number $d$ ($d$ maybe $\gcd(a,b)$, $\gcd(a,c)$ or $\gcd(b, c)$).
3. He writes the number $d$ to the board two times.
It can be seen that after performing the move $n-2$ times, there will be only two numbers with the same value left on the board. Alex wants to know which numbers can left on the board possibly. Can you help him?