Statement

William's new web portal arenafreaks.net is struggling to take off. As the large bill from the virtual machines provider is expected to arrive sooner and sooner, William is getting frenzied by the addition of new features to the portal, and in particular to its flagship: the game database. As a matter of fact, a couple of days ago William added a database section for capture-the-flag games, as usual transcribed in arenaic notation. The transcription of a capture-the-flag game between N teams in arenaic notation consists in a series of E events, each described by two integers X_i and Y_i from 0 to N-1 representing: (1) if X_i ≠ Y_i, that team X_i stole Y_i's flag and is running to score a point; (2) if X_i = Y_i, that team X_i recovered his flag (from the last team which stole it) preventing them from scoring a point...