This is regarding the number post-quantum key exchange protocol New-Hope (https://eprint.iacr.org/2015/1092.pdf). In the paper, we can see that the number of samples generated by the protocol is $2n$ where $n$ is $1024$, the rank of matrix $a$. Once in server side $b\leftarrow as+e$ and once in client side $u\leftarrow as'+e'$. But the authors in the paper (page 18 appendix B) says that the number of samples in each instantiation of the protocol is $5n$.
I can't understand why. Also, as far as I know the LWE samples are related when the matrix $a$ and the secret $s$ remains same. But, in the protocol the secret changes $s$ and $s'$.
Can someone please explain this? Thank you in advance.