Calculate inverse modulo: $8^{-13}\pmod {29}$

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How can I calculate $8^{-13}\pmod{29}$ ? I don't get how it works. Can I do it separately? So first $8^{-13}$ and then modulo $29$. And how can I calculate a negative power the quickest?

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HINT:

Using Fermat's Little Theorem, $\displaystyle2^{28}\equiv1\pmod{29},$

$\displaystyle8^{-13}=(2^3)^{-13}=2^{-39}\equiv (2^{28})^{(-2)}\cdot2^{17}\equiv2^{17}\pmod{29}$

Now, observe that $\displaystyle2^5=32\equiv3\pmod{29}$

Can you take it from here?