1 1
2 2
3 3
4 4
5 5
6 6
7 7
8 8
9 9
10 90
11 909
12 9090
13 90909
14 909090
15 9090909
16 90909090
17 909090909
18 9090909090
19 90909090909
20 909090909090
21 9090909090909
22 90909090909090
23 909090909090909
24 9090909090909090
25 90909090909090909
26 909090909090909090
27 9090909090909090909