In the test set, 105 out of 400 samples have only one heavy atom as a ligand to generate and half of the complexes have less than 5 heavy atoms to generate. We believe it is easy for LigandDiff to sample valid complexes under such conditions. To strictly evaluate the performance of LigandDiff, we randomly sample the size of the generated ligands in the range of 6 to 20. This range was chosen because it only covers 41.7% of the size distribution in the training dataset while 51.5% of the diffused ligands in the training set have 5 heavy atoms or less. The results are reported in Table . Although this size sample is challenging for LigandDiff, it still shows remarkable performance.