Use Fermat's little theorem to find remainder of powers

I have to use Fermat’s little theorem to find the value of$$
x \uparrow \uparrow k \mod m = \underbrace{x^{x^{{}^{{{.\,}^{.\,^{.\,^{x}}}}}}}}_{k\text{ times}} \mod m,$$
where $x$ is repeated in power $k-1$ times and $m$ is any number.

That is, if $x=5$, $k=3$ and $m=3$, then I need to find $\ 5^{5^5} \mod 3$ .

Also note that $x$ is always a prime number.

It has been in my mind for quite a while now I can’t find an answer.

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