Here is the code and the solution:

function figureArea(w, h, W, H) {
var s1 = w * h;
var s2 = W * H;
var s3 = Math.min(w, W) * Math.min(h, H);
//let [s1,s2,s3]=[w * h, W * H, Math.min(w, W) * Math.min(h, H)];
console.log(s1 + s2 - s3);
}
figureArea(13, 2, 5, 8);