Climbing level 2: 2 kinds
Climb the third level: 1+2=3 kinds (the previous step starts from 1 or the second level).
Climbing Level 4: 2+3=5 kinds (the previous step starts from Level 2 or Level 3).
Grade 5: 3+5=8 kinds.
Grade 6: 5+8= 13 species.
Grade 7: 8+ 13=2 1 species.
Grade 8: 13+2 1=34 species.
Climbing level 9: 2 1+34=55 kinds.
Grade 10: 34+55=89 kinds.