/***
!Test
expected: !Result
  status: SATISFIED
  solution: !Solution
    _output_item: Ok
***/

constraint iffall([]) = true;
constraint iffall([false]) = true;
constraint iffall([true]) = false;
constraint iffall([false, true]) = false;
constraint iffall([true, false]) = false;
constraint iffall([true, true]) = true;
constraint iffall([false, false]) = true;

solve satisfy;
output ["Ok"];