We tested two ways of representing input molecules: (1) as sequences of symbols, using the SMILES notation and (2) as the combination of molecular fingerprints, where structural information is represented by bits in a bit string. The SMILES representation as input for a DL model was based on the DeepCCI by Kwon et al. Model input has to be numerical, so SMILES notation was one-hot encoded (Figure ). This means that every character of the SMILES string was represented by a binary vector of size 35, with all but its corresponding entry set to zero. SMILES were padded to the length of the longest string, 94.