Cohomology of finite modules over short Gorenstein rings

Let $R$ be a Gorenstein local ring with maximal ideal $\mathfrak{m}$ satisfying ${\mathfrak{m}}^3=0\mathrm{\ne }{\mathfrak{m}}^2$. Set $k=R\mathrm{/}\mathfrak{m}$ and $e={\text{rank}}_k(\mathfrak{m}\mathrm{/}{\mathfrak{m}}^2)$. If $e>2$ and $M$, $N$ are finitely generated $R$-modules, we show that the formal power series $\sum_{i=0}^\infty$\text{rank}${k}\left($\text{Ext}$^i_R(M,N)\otimes_R k \right)t^i$and$\sum{i=0}^\infty$\text{rank}$_{k}\left($\text{Tor}$_i^R(M,N)\otimes_R k \right)t^i$arerational,withdenominator$1-et+t^2$.