3. Given the equalities $\log _{a} b+\log _{b} c+\log _{c} a=\log _{b} a+\log _{c} b+\log _{a} c=-1$. Find $\log _{a} b$.

If there are multiple answers, list them in ascending order separated by a semicolon.
Answer: $-1 ; 1$

## Examples of answer notation:

$1 / 4$

0,25 ; 0,5$

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