static S ai_ifAndInput(S rule, S input) {
  new Matches m;
  if (!simpleStarMatchOnCTokensIC("if * and input * then say *",
    javaTokDroppingBracketsC_unquote(rule), m)) throw UnsuitableRule;
  if (!match($2, input)) null;
  T3<S> t = ai_tripelize(ai_bigXToDollarX($1));
  printStruct(+t);
  S x = random(ai_texts(t));
  if (x == null) null;
  ret ai_replaceBigX($3, x);
}