Consider the arithmetic operations \(\blacktriangle\) and \(\blacktriangledown\) defined by

\[\large \begin{align} a \blacktriangle b & = \begin{cases} a & \text{ if } \lvert a \rvert \geq \lvert b \rvert \\ b & \text{ if } \lvert a \rvert < \lvert b \rvert \end{cases} \\ a\blacktriangledown b & = \begin{cases} a & \text{ if } \lvert a \rvert \leq \lvert b \rvert \\ b & \text{ if } \lvert a \rvert > \lvert b \rvert \end{cases} \end{align} \]

How many integers \(k\) are there such that \((-20 \blacktriangle 9) \blacktriangledown (k \blacktriangle 5)=5?\)

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