input:

100
1 4
2 1
2 2
2 3
3 6
4 2
4 3
4 4
4 5
5 4
6 1
6 2
6 4
7 1
8 3
8 7
8 8
8 14
9 4
10 1
10 2
10 3
12 2
12 3
12 4
12 8
13 2
14 1
14 2
14 4
15 4
16 9
16 15
16 16
16 28
17 6
18 1
18 2
18 4
19 5
20 1
20 3
20 4
20 6
21 1
22 1
22 2
22 3
23 4
24 5
24 7
24 8
24 15
25 3
26 1
26 2
26 3
27 5
28 1
28 3
28 4
28 6
...

output:

Impossible
2 1
Impossible
Impossible
Impossible
2 1 4 3
3 4 1 2
2 1 4 3
3 4 1 2
4 3 2 1
Impossible
Impossible
Impossible
2 1 4 3 6 5
Impossible
Impossible
Impossible
2 1 4 3 6 5 8 7
3 4 1 2 7 8 5 6
4 3 2 1 8 7 6 5
2 1 4 3 6 5 8 7
3 4 1 2 7 8 5 6
4 3 2 1 8 7 6 5
5 6 7 8 1 2 3 4
6 5 8 7 2 1 4 3
7 8 5 ...

result:

wrong answer 53rd lines differ - expected: '9 10 11 12 13 14 15 16 1 2 3 4 5 6 7 8', found: '9 10 11 12 13 14 15 16 9 10 11 12 13 14 15 16'