Character string divider divides a targeted character string into a plurality of groups at each bonding sites on a main chain. In the character string dividing process, the character string divider adds starting/ending symbols to the targeted character string, inserts a delimiter between adjacent characters, changes a notation related to oxo acids, reconstructs an atomic symbol consisting of two characters, changes a notation regarding a subscript or superscript, links hydrogen to another element, reconstructs a set of side chains, reconstructs a character string consisting of one group, reconstructs a back-end group, reconstructs a double bond in a group, and removes the starting/ending symbols. Character string reverser reverses the alignment of the groups.