Computer Programming Contest Preparation

    1 0:
    2 1: 1
    3 2: 2
    4 3: 3
    5 4:
    6 5: 5 22 0
    7 6: 6 14 13
    8 7: 7
    9 8:
   10 9:
   11 10: 10 15 12 4
   12 11: 11
   13 12:
   14 13:
   15 14:
   16 15:
   17 16:
   18 17: 17
   19 18: 18
   20 19: 19
   21 20: 20 8
   22 21: 21 9 16
   23 22:
   24 23: 23