1. 20.
    0
    ···
  2. 19.
    +2
    ···
    1. 1.
      +1
      ···
  3. 18.
    +4 -2
    ···
    1. 1.
      +1
      ···
      1. 1.
        +1
        ···
      2. 2.
        +1
        ···
  4. 17.
    0
    ···
    1. 1.
      +2
      ···
  5. 16.
    +1
    ···
    1. 1.
      0
      ···
    2. 2.
      0
      ···
  6. 15.
    +3 -2
    ···
    1. 1.
      -1
      ···
      1. 1.
        0
        ···
  7. 14.
    +2 -1
    ···
    1. 1.
      0
      ···
  8. 13.
    +1
    ···
    1. 1.
      +1
      ···
  9. 12.
    +2
    ···
    1. 1.
      +2 -1
      ···
      1. 1.
        +2
        ···
  10. 11.
    0
    ···
  11. 10.
    +1
    ···
    1. 1.
      +1
      ···
  12. 9.
    +1
    ···
    1. 1.
      0
      ···
      1. 1.
        0
        ···
      2. 2.
        +1
        ···
  13. 8.
    +2
    ···
    1. 1.
      +1
      ···
  14. 7.
    +1
    ···
    1. 1.
      +1
      ···
  15. 6.
    +1
    ···
    1. 1.
      +1
      ···
  16. 5.
    +1 -1
    ···
    1. 1.
      -1
      ···
      1. 1.
        +1
        ···
  17. 4.
    +1
    ···
    1. 1.
      0
      ···
    2. 2.
      +1
      ···
  18. 3.
    +2
    ···
    1. 1.
      +1
      ···
      1. 1.
        +2 -1
        ···
  19. 2.
    +1
    ···
    1. 1.
      +1
      ···
      1. 1.
        -1
        ···
      2. 2.
        +3
        ···
  20. 1.
    +16 -6
    ···