And we have a pair of electrons which aren't drawn. Here, let me fill them in. We have a pair of electrons on this oxygen. So all four types of orbitals are filled. So that means if we don't have our bonding orbitals our Sigma bonding, we must use our Sigma antibodies. So the lowest unoccupied molecular orbital is the anti unoccupied Sigma antibonding orbital of one of the ho bonds.