For some matrix $\mathbf{P} = \begin{pmatrix} a & b \\ c & d \end{pmatrix}$ with nonzero integer entries,
\[\begin{pmatrix} 4 & 3 \\ -1 & 0 \end{pmatrix} = \mathbf{P}^{-1} \begin{pmatrix} 1 & 0 \\ 0 & 3 \end{pmatrix} \mathbf{P}.\]Find the smallest possible value of $|a| + |b| + |c| + |d|.$

Let's think step by step and output the final answer within \boxed{}.
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