ortools-clone/examples/flatzinc/sum_ctr.fzn

var 6..6: s :: output_var = 6;
array [1..3] of var 1..5: x :: output_array([1..3]);
constraint int_lin_ne([-1, 1, 1, 1], [s, x[1], x[2], x[3]], 0);
solve satisfy;