let $\mathrm{p}, \mathrm{q}$ be integers and let $\alpha, \beta$ be the roots of the equaion, $\mathrm{x}^2-\mathrm{x}-1=0$, where $\alpha \neq \beta$. For $\mathrm{n}= 0,1,2, \ldots \ldots$, Let $\mathrm{a}_{\mathrm{n}}=\mathrm{p} \alpha^{\mathrm{n}}+\mathrm{q} \beta^{\mathrm{n}}$ FACT : If $a$ and $b$ are rational nubers and $a+b \sqrt{5}=0$, then $a=0=b$. If $a_4=28$, then $p+2 q=$