said {HEAD ~ internal signal} is issued from a connection node between said {TAIL ~ second P channel MOS transistor} and said first N channel MOS transistor 
said { HEAD ~ internal signal } is issued from a connection node between said { TAIL ~ second P channel MOS transistor } and said first N channel MOS transistor
OTH 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 OTH