7.6 On a horizontal line, points $A$ and $B$ are marked, the distance between which is 4. Above the line, two semicircles with a radius of 2 are constructed, centered at points

A and B. Additionally, one circle, also with a radius of 2, is constructed, for which the point of intersection of these semicircles is the lowest point - see the figure. Find the area of the figure obtained by subtracting from the area of the circle the parts common to it and the two semicircles (the shaded area in the figure). Justify your answer.