The problem goes as followed: multiple balls have been tossed into a box, but we do not know how many that were tossed. However, we know that 5 of the balls that were tossed had a blue colour ($y=5$), and that the probability $p$ of tossing a blue ball is 30%. We also know that \begin{align} y \sim Bin(n,p) \end{align}
Thereby, my question is: how should the likelihood function, $L(n|y=5,p=0.30)$, be formulated, and how should I go about deriving the maximum likelihood estimate of $n$ in this setting, where $n$ is discrete?
Any help is highly appreciated!