{HEAD ~ a fourth N channel MOS transistor} connected between the other conductive terminal of said {TAIL ~ fourth P channel MOS transistor} and the ground potential, and 
{ HEAD ~ a fourth N channel MOS transistor } connected between the other conductive terminal of said { TAIL ~ fourth P channel MOS transistor } and the ground potential , and
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH