设 $\boldsymbol{\alpha}_{1}, \boldsymbol{\alpha}_{2}, \boldsymbol{\alpha}_{3}$ 均为 3 维列向量, 记矩阵
$$
\boldsymbol{A}=\left(\boldsymbol{\alpha}_{1}, \boldsymbol{\alpha}_{2}, \boldsymbol{\alpha}_{3}\right), \boldsymbol{B}=\left(\boldsymbol{\alpha}_{1}+\boldsymbol{\alpha}_{2}+\boldsymbol{\alpha}_{3}, \boldsymbol{\alpha}_{1}+2 \boldsymbol{\alpha}_{2}+4 \boldsymbol{\alpha}_{3}, \boldsymbol{\alpha}_{1}+3 \boldsymbol{\alpha}_{2}+9 \boldsymbol{\alpha}_{3}\right) \text {. }
$$
如果 $|\boldsymbol{A}|=1$, 那么 $|\boldsymbol{B}|=$