Computer Programming Contest Preparation

    1 20
    2 1
    3 2
    4 3
    5 4
    6 5
    7 6
    8 7
    9 8
   10 9
   11 10
   12 11
   13 112
   14 123
   15 444
   16 35
   17 944
   18 34
   19 87
   20 9
   21