1 -> 10, 20, 30, 40
10 -> 100, 101, 102
100 -> no data
101 -> 1011
1011 -> no data
102 -> no data

20 -> no data

30 -> 301, 302
301 -> no data
302 -> no data

40 -> 401, 402
401 -> 4011
4011 -> 40111
40111 -> no data
402 -> no data