Let $\mathbb{N}$ be the set of natural numbers and a relation $R$ on $\mathbb{N}$ be defined by \[ R=\{(x,y)\in \mathbb{N}\times \mathbb{N} : x^{3}-3x^{2}y-xy^{2}+3y^{3}=0\}. \] Then the relation $R$ is: