We thank all reviewers for giving us the insightful comments

We thank all reviewers for giving us the insightful comments. Then we collect all positive samples by a Breadth-First Search algorithm. We will add these results to our paper. We also give the qualitative analysis in Figure 2 (b). About the baseline, our baseline is the KNN method, i.e. directly using the nearst We have compared our algorithm with the KNN algorithm in Sec 4.2.