Please, solve the following digital electronics/computer problem. Step by step solution will be very much appreciated.

The full subtractor is a combinational circuit, which is used to perform subtraction of three input bits: the minuend X, subtrahend Y, and borrow in Bm. The full subtractor generates two outputs bits: the difference D and borrow out B B is set when the previous digit borrowed from X. Thus, Bn is also subtracted from X as well as the subtrahend Y, or in symbols: X-Y- B.The full subtractor generates a borrow out when it needs to borrow from the next digit. Since we are subtracting X by Y and By a borrow out needs to be generated when X