Computer Programming Contest Preparation

    1 3
    2 3
    3 -1
    4     6
    5     10
    6     4
    7     -5
    8     4
    9     -3
   10     4
   11     4
   12     -4
   13     4
   14     -5
   15     4
   16     -2
   17     -3
   18     -4
   19