Matrix Sum Multiplication

You are given a matrix with $N$ rows (numbered $1$ through $N$) and $M$ columns (numbered $1$ through $M$). Initially, all cells of this matrix contains $0's$. Let's denote a cell in row $x$ and column $y$ by ($x$,$y$). You have to process $Q$ queries in which you have to perform single operation as described below: - Consider a cell($x,$$y$). - Add $Z$ to all the cells in row $x$. - Add $Z