If we define $\otimes(a,b,c)$ by
\begin{align*}
\otimes(a,b,c) = \frac{\max(a,b,c)- \min(a,b,c)}{a+b+c-\min(a,b,c)-\max(a,b,c)},
\end{align*}
compute $\otimes(\otimes(7,1,3),\otimes(-3,-4,2),1)$.

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