已知 3 阶行列式 $\left|\begin{array}{ccc}a_{11} & 2 a_{12} & 3 a_{13} \\ 2 a_{21} & 4 a_{22} & 6 a_{23} \\ 3 a_{31} & 6 a_{32} & 9 a_{33}\end{array}\right|=6$ ，则 $\left|\begin{array}{lll}a_{11} & a_{12} & a_{13} \\ a_{21} & a_{22} & a_{23} \\ a_{31} & a_{32} & a_{33}\end{array}\right|=$