// Time:  O(1)
// Space: O(1)

class Solution {
public:
    int computeArea(int A, int B, int C, int D, int E, int F, int G, int H) {
        return (D - B) * (C - A) +
               (G - E) * (H - F) -
               max(0, (min(C, G) - max(A, E))) *
               max(0, (min(D, H) - max(B, F)));
    }
};