Dual 3-input NOR gates and inverter.
+---+--+---+ ________
|1 +--+ 14| VCC /1Y=1A+1B+1C
|2 13| 3C
1A |3 12| 3B __
1B |4 4000 11| 3A /2Y=2A
1C |5 10| /3Y
/1Y |6 9| /2Y ________
GND |7 8| 2A /3Y=3A+3B+3C
+----------+
