How to solve this limit problem?-$lim_{nto infty} left(frac{ n!}{(mn)^n}right)^{frac{1}{n}}$

I need to find the value of-

$$\lim_{n\to \infty}\ \left(\frac{\ n!}{(mn)^n}\right)^{\frac{1}{n}}$$

where $m {\in} R$

I don't know how to even start. Would someone explain it step by step, also which type of indeterminate form is this?
Is there a simpler to solve this ? i.e. without any high mathematics theorem etc.?