A $2023 \times 2023$ grid of lights begins with every light off. Each light is assigned a coordinate $(x, y)$. For every distinct pair of lights $(x_1, y_1)$ and $(x_2, y_2)$, with $x_1 < x_2$ and $y_1 > y_2$, all lights strictly between them (i.e., $x_1 < x < x_2$ and $y_2 < y < y_1$) are toggled. After this procedure is done, how many lights are on?

Let's think step by step and output the final answer within \boxed{}.
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