c Pigeonhole principle formula for 4 pigeons and 3 holes c Generated with `cnfgen` c (C) 2012-2016 Massimo Lauria c https://massimolauria.github.io/cnfgen c c COMMAND LINE: cnfgen php 4 3 c p cnf 12 22 1 2 3 0 4 5 6 0 7 8 9 0 10 11 12 0 -1 -4 0 -1 -7 0 -1 -10 0 -4 -7 0 -4 -10 0 -7 -10 0 -2 -5 0 -2 -8 0 -2 -11 0 -5 -8 0 -5 -11 0 -8 -11 0 -3 -6 0 -3 -9 0 -3 -12 0 -6 -9 0 -6 -12 0 -9 -12 0