Stores the Tree
tr = [ [ ] for i in range ( n + 1 ) ] NEW_LINE tr [ 0 ] . append ( 3 ) NEW_LINE tr [ 0 ] . append ( 4 ) NEW_LINE tr [ 4 ] . append ( 6 ) NEW_LINE tr [ 6 ] . append ( 2 ) NEW_LINE tr [ 2 ] . append ( 1 ) NEW_LINE tr [ 2 ] . append ( 8 ) NEW_LINE tr [ 8 ] . append ( 5 ) NEW_LINE tr [ 5 ] . append ( 7 ) NEW_LINE