/**
 * This class counts the number of variables appearing in the given formula.
 *
 */
class VariableCounter extends TUCombinerFloatAdd {

Float apply(Variable v) { 
  System.out.println("in apply Variable; return 1");
  return 1.0f; }

static Float countVariables(Object o){
    return traverse(o, new VariableCounter());
}
}