For the logic circuit in the figure (inputs A, B, C; gates G1 to G4), derive the Boolean expression for the output Y and build its truth table. Number each input row m = 4A + 2B + C (so m runs from 0 to 7). Determine (a) the number of input combinations for which Y = 1, and (b) the sum of the row numbers m of all rows for which Y = 1.