334

Problem ID: 334

Though this isn't stated in the problem, the number vertices that appear in the input is less than or equal to 200.

Also, take note of where the trailing spaces appear and where they don't in the sample output below. Otherwise, this could result in a presentation error. The sample input has been uploaded on uDebug.

Case 1, 2 concurrent events:[no trailing space]
(e1,e4) (e2,e4) [trailing space]
Case 2, 10 concurrent events:[no trailing space]
(two,four) (two,five) [trailing space]
Case 3, no concurrent events.[no trailing space]
Case 4, 1 concurrent events:[no trailing space]
(alpha,gamma) [trailing space]