hydrogens that undergo change. In cases where multiple potential solutions exist, we handle hydrogen reattachment by considering multiple AAMs in the subsequent analysis steps. If all AAMs α are identical, or all extended ITS graphs Υ(G ′ , H ′ , α ′ ) are isomorphic, for all the possible extensions α ′ , G ′ and H ′ of, respectively, α, G and H due to addition of hydrogens, then we adopt a single representative as the complete ITS.