How to apply Rouché's theorem

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I'm new on stack Exchange

I have a problem I think I can solve using Rouché's theorem But I have no idea how to start.

How should i show that $$f(z) = 5\sin(z) - e^z$$ has exactly 1 zero in the square with the origin as center and sides having length $\pi$?

Using Rouché's theorem, I should probably say that $$|5\sin(z)|<|e^z|$$ But I cant understand why.

Im so sorry for my bad english and probably stupid question But i cant figure it out myself

Thank you in advance :)