1. Define a new operation " $\otimes$ ": $a \otimes b=\frac{(a+1)(b-1)}{a \times b}-1$, then the calculation result of $(43 \otimes 47) \times 43 \times 47$ is $\qquad$ .
【Match the answer】3

Translate the text above into English, please retain the original text's line breaks and format, and output the translation result directly.