And now we move to adding three-bit numbers: a will consist of three bits a2 a1 a0 and b will consist of three bits b2 b1 b0. If we add them, the result will be s, consisting of four bits s3 s2 s1 s0. d3 d2 d1 a2 a1 ao + b b1 bo S3 S2 81 80 Where d3, d2 and d1 are called third, second and first carry bits respectively. The formulas for so and s1 are the same as before, so we are not asking you for them. We are asking you for s2 and s3. a) Write a boolean formula for s2. Submit a file named p2a.py. b) Write a boolean formula for s3. Submit a file named p2b.py. Note: Your submitted Boolean formulas for s2 and s3 should only consist of a0, a1, a2, b0, b1 and b2. It means that your formulas must not have carry bits d1, d2 and d3. Note that you can find the carry bits as a function of other bits.