case 1 failed
input:
5
1 2
2 3
3 4
1 5
expected:
0.156250000
0.140625000
0.156250000
0.273437500
0.273437500
got:
0.15625000100000000000
0.14062500100000000000
0.15625000100000000000
0.27343750100000000000
0.27343750100000000000