# Complexity of multiplying two integers of size \$ n \$ and \$ m \$

The multiplication of two integers in size. $$n$$ It can be done in time $$O (n cdot log n cdot log log n)$$ using the FFT method.

If the two integers have different sizes $$n$$ Y $$m$$, makes an upper limit using $$n$$ Y $$m$$ exists?