4
0 1 0 0
0 0 2 0
0 3 0 0
0 0 0 4
% Quasigroup completion problem. 
% This problem file is used by 
% http://www.hakank.org/comet/quasigroup_completion.co
% 
% Example from Gomes & Shmoys, page 7
% Two solutions.