Let $f=u+iv$ is an entire function. If $u+v$ is bounded then is $f$ constant or not? $(u=Ref(z)$ and $v=Imf(z))$

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$u+v$ is bounded $\Rightarrow$ $(u+v)^2=u^2+v^2+2uv$ is bounded $\Rightarrow$ $|f|^2+2uv$ is bounded.

What can I do further to reach the conclusion? or this is not the way to reach there?

Thank you.

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Hint: One approach is to use the fact that if the real part of an entire function is bounded, then the function is constant. Can you construct from $f$ an entire function whose real part is $u+v$?