You are asked to provide a circuit that will add 2 4-bit sign-magnitude numbers. However, your circuit must include two 4-bit 2s complement adders with 2 4-bit inputs and a 4-bit result. You may use multiplexers (only 2:1 muxes) and simple gates (only inverters and 2-input gates for AND, OR, and XOR) on the inputs of the adders. The sign-magnitude numbers have 1 bit for the sign and 3 bits for their value. Make sure to explain how your circuit accomplishes the addition in words as well as figures.