Procedure Add IC 74LS32 into ICBase-1 (74LS32).Add IC 74LS27 into ICBase-2 (74LS27).Add IC 74LS21 into ICBase-3 (74LS21).Connect Input-13 to Pin-1 (Input) of ICBase-1 (74LS32).Connect Pin-2 (Input) of ICBase-1 (74LS32) to Input-12.