0 -> 1
1 -> 1
2 -> 2
3 -> 3
4 -> 5
5 -> 10
6 -> 12
7 -> 22
8 -> 36
9 -> 58
10 -> 88
11 -> 147
12 -> 227
13 -> 369
14 -> 588
15 -> 947
16 -> 1498
17 -> 2415
18 -> 3833
19 -> 6138
20 -> 9866
21 -> 15807
22 -> 25186
23 -> 40318
24 -> 64581
25 -> 103484
26 -> 165775
27 -> 265504
28 -> 424813
29 -> 680565
30 -> 1091140
31 -> 1750482
32 -> 2808050
33 -> 4504189
34 -> 7224290
35 -> 11590195
36 -> 18597887
37 -> 29845724
38 -> 47903678
39 -> 76913321
40 -> 123536994
41 -> 198493224
42 -> 319012167
43 -> 512782858
44 -> 824324291
45 -> 1325287631
46 -> 2131033866
47 -> 3427343326
48 -> 5513397398
49 -> 8871060819
50 -> 14276520317