Sum of Xors

You are given a grid of size $N\times M$ $(N$ and $M$ are both even$)$, where each cell of the grid has value $0$. Let $R_i$ denote the [bitwise XOR](https://en.wikipedia.org/wiki/Bitwise_operation#XOR) of all elements of the $i^{th}$ row and $C_i$ denote the bitwise XOR of all elements of the $i^{th}$ column. *Ugliness* of a grid is defined as $\displaystyle{\sum_{i=1}^{N} R_i + \sum_{i=1}^{M}