sS ai_ruleOfThree_solver_1(S db, S input) {
  new TransformersOnObjects too;
  too.addAll(lambdaMap ai_parseBasicLogicRule(tlft(db)));
  too.addAll(Input(input));

  // for word appearing in LHS and RHS: turn word into variable
  too.addTransformer(func(BasicLogicRule<S> r) -> BasicLogicRule {
    LS words = antiFilter isDollarVar(sharedWords(r.lhs, r.rhs));
    SS map = ciMapWithUnusedCountingDollarVars(words, linesLL(r.lhs, r.rhs));
    ret mapBasicLogicRule(r, s -> replaceCodeTokensUsingMap(s, map));
  });

  // match input with rules
  too.addTransformer(func(BasicLogicRule<S> r) {
    if (containsDollarVars(r.in))
      too.addTransformer(func(Input i) {
        S s = cast i.a;
        for (SS map : flexMatchDollarVarsIC_all(r.in, s))
          too.add(Input(replaceVars(r.out)));
        null;
      });
    null;
  });

  too.think();
  
  null;
}