C[C@@H](Cc1ccc(C=O)cc1)NC[C@@H](O)c1ccc(O)c(NCO)c1.C[C@@H](Cc1ccc(C=O)cc1)NC[C@@H](O)c1ccc(O)c(NCO)c1.O=C(O)/C=C/C(=O)O
The donor in a hydrogen bond is usually a strongly electronegative atom such as N, O, or F that is covalently bonded to a hydrogen bond. How many hydrogen bond donors does the molecule have?