What is the Boolean expression for the output F of the combinational logic circuit of NAND gates given below:
F=(¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯PQ.¯¯¯¯¯¯¯¯¯QR).¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯(¯¯¯¯¯¯¯¯PR.¯¯¯¯¯¯¯¯¯QR)
F=¯¯¯¯¯¯¯¯PQ.¯¯¯¯¯¯¯¯¯QR+(¯¯¯¯¯¯¯¯PR.¯¯¯¯¯¯¯¯¯QR)
F=¯¯¯¯Q+¯¯¯¯R