# A Mysterious Recursion

Algebra Level 2

The function $$f$$ is defined only on integer values as follows:

$f(x) = \begin{cases} x+10 & \mbox{when } x < 10 \\ f(x-5) & \mbox{when } x \geq 10 \\ \end{cases}$

What is the maximum value of the function?

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