% RUNS ON flatzinc
% RUNS ON fzn_bdd_canon
% RUNS ON fzn_fd_canon
% RUNS ON fzn_fdlp_canon
% RUNS ON fzn_lazyfd_canon
% RUNS ON fzn_sat_canon

var bool: x1 :: output_var;
var bool: x2 :: output_var;
constraint bool_not(false, true);
constraint bool_not(true, false);
constraint bool_not(x1, x2);
solve satisfy;