R1 -> 17 1 20 12
R2 -> 4
R1 -> 21 13 24
    4
17  21
1   13
20  24
12

R2-> 6
R1 -> 19 30 31 27

    4    6
17  21   27
1   13   19
20  24   30
12       31

R2-> 3
R1 -> 22 34

    4    6    3
17  21   27
1   13   19   22
20  24   30   
12       31   34     ...

...