Case 1:
  1
     2
        4
     3

Case 2:
  1
     2

Case 3:
  7
     3
  6
     4
        1
        2
  5

Case 4:
  1
     4
     5
        3
  2

Case 5:
  1
     6
        4
        5
           3
  2

Case 6:
  1
     2
     4
    11
    14
    15
 17
     8
    16
    18
       19
          20
    24
    27
       10
           9
       26
          25
 22
    13
       12
       23
           5
    21
        3
        7
           6