FPC21-003.Fraud Checking

The exam of the First Programming Course (FPC) was a success: all students have passed, with excellent grades! In fact, they have done so well, that it is somewhat suspicious. It is time to do a fraud check, but nobody has time to sift through the hundreds of code submissions manually. Therefore, you have been tasked with finding code submissions that are similar in structure: you should make a fraud report if the only difference between two pieces of code is the renaming of some variables.

More precisely, one piece of code is similar to another when it is possible to make the two pieces of code identical to each other by processing a sequence of word replacements. When, after processing all word replacements, the first piece of code is identical to the second piece of code, and this also applies vice versa, then the two pieces of code are similar.

Each word replacement should replace all occurrences of a word. A word replacement can only replace a complete word. Spaces between words or at the start/end of a line should be ignored, but newlines cannot be ignored: for two pieces of code to be similar, each line of the first piece should have the same number of words as the same line in the second piece.

Given two pieces of code, check whether they similar. If they are similar, print a fraud report that gives the sorted list of word replacements.