I couldn't find this particular approach in existing editorials, so I decided to share it.

1. Problem

You are given a 2D table $$$a$$$ with $$$n$$$ rows and $$$m$$$ columns. You need to answer $$$q$$$ queries offline. Each query is four integers $$$x_1$$$ $$$y_1$$$ $$$x_2$$$ $$$y_2$$$ describing a rectangle. For each query, you need to output