Why this nput works in TEST problem

I was going through practice and saw that following when entered as TEXT was accepted as successful submission. Is it Bug or something else. Enter the following as TEXT instead of other language from list for http://www.codechef.com/problems/TEST and submit. can we do same for other problems also?
Input:
1
2
3
4
5
6
7
8
9
0
9
8
7
6
5
4
3
2
1
11
21
31
41
51
61
71
81
91
99
89
79
69
59
49
39
29
19

If i print the above series in c++, even that is passing the system tests. See this. I guess this series will pass for all languages. The point that is troubling me is why is it passing the cases? @admin can you please explain.

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