$3\ast 4$ means $3$ is the mother of $4$.
$3\#4$ means $3$ is the father of $4$.
$3@4$ means $3$ is the brother of $4$.
$3\&4$ means $3$ is the daughter of $4$.
$3+4$ means $3$ is the son of $4$.

According to $\text{L}@\text{M}\&\text{N}\#\text{O}+\text{P}\ast \text{Q}\#\text{R}$, how is $\text{M}$ related to $\text{R}$?

Let's decode the given relationship string step-by-step:
* $\text{L}@\text{M}⟹\text{L}$ is the brother of $\text{M}$.
* $\text{M}\&\text{N}⟹\text{M}$ is the daughter of $\text{N}$ (so $\text{M}$ is female).
* $\text{N}\#\text{O}⟹\text{N}$ is the father of $\text{O}$. Thus, $\text{L, M,}$ and $\text{O}$ are siblings (children of $\text{N}$).
* $\text{O}+\text{P}⟹\text{O}$ is the son of $\text{P}$. Since $\text{N}$ is the father, $\text{P}$ must be the mother.
* $\text{P}\ast \text{Q}⟹\text{P}$ is the mother of $\text{Q}$. Thus, $\text{Q}$ is also a sibling to $\text{L, M,}$ and $\text{O}$.
* $\text{Q}\#\text{R}⟹\text{Q}$ is the father of $\text{R}$.

Since $\text{M}$ is a female sibling of $\text{Q}$, and $\text{Q}$ is the father of $\text{R}$, $\text{M}$ is the paternal aunt ($\text{Bua}$) of $\text{R}$.