We operated under the assumption that the reference route represents the optimal synthetic pathway for each target molecule within its respective route set. To produce a universal and interpretable score for the route, we proposed utilizing the Tree Edit Distance (TED) between any given route and the reference route as a simple but still robust metric for assessing the quality of the route. This approach allowed us to quantitatively measure the similarity between the synthetic routes, with the TED serving as a suitable prior for the evaluation score. Therefore, the scoring model was trained to predict the distance between the proposed route and the reference route as the target.