The figure shows six circles just touching each other and just touching the four sides within a rectangle. The rectangle measures 42 $$cm$$ by 28 $$cm$$. <hr> What is the area of the shaded part? (Take π = $$\frac{22}{7}$$) <br> <input min="0" type="number" id ="imp6pg199q7b_1" class="lineinput" placeholder="?" /> $$cm^2$$