A lookup table with low power consumption is provided. The lookup table includes a memory element including a transistor and a capacitor. A drain of the transistor is connected to one electrode of a capacitor and the input of an inverter, and a source is connected to a first wiring. The other electrode of the capacitor is connected to a second wiring. In such a memory element, the potential of the second wiring is complementary to the potential of the first wiring when writing data; accordingly, the potential of the drain of the transistor, i.e., the potential of the input of the inverter can be higher than the high potential of the inverter. Thus, shoot-through current of the inverter at this time can be significantly reduced. As a result, power consumption in a standby state can be significantly reduced.