<image>As shown in the figure, given the parabola y = x^2 + 2x - 3, the parabola is translated downward along the y-axis. The shaded area enclosed by the translated parabola and the original parabola with the two vertical lines passing through the points (-4,0) and (2,0) and parallel to the y-axis is s. Let the translation distance be m. Find the function relationship between s and m. _(Do not write the range of the independent variable).

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