Consider a1, 22, ..., An, bi, b2, ..., bn, S1, S2, ..., Sn+1 {0,1}, and let n-digit binary addition be as shown in the following equation, [sn+15nSn-1 ... 81] = [anan-1 ... ai] + [bnbn-1...b). For example, [110] = [11] + [11]. Let ^,V, and denote AND, OR, and NOT Boolean operators, respectively. (4) Write a Boolean expression of snti with 21, 22, ..., An, b1,b2, ..., bn