How to evaluate double integral of an irregular surface using Monte Carlo Simulation

Hi Everyone,

Please how can I use Monte Carlo Simulation to evaluate the double integral of an irregular surface. There is no defined function for this surface. All I was told is to generate a discretized matrice of 0 and 1 such that the evaluation is done with the elements of the matrice with 1 and the element with 0 aren't considered for the evaluation. The function to be used for evaluation is x^2 + y^2. If there are other viable methods you know, kindly help out on this

Thanks.