input:

499991 31473
1 2
2 3
1 4
2 5
4 6
4 7
6 8
4 9
8 10
6 11
9 12
10 13
10 14
1 15
14 16
3 17
14 18
12 19
13 20
11 21
16 22
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5 25
16 26
18 27
8 28
15 29
27 30
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27 35
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11 40
17 41
25 42
3 43
3 44
2 45
35 46
25 47
5 48
6 49
41 50
42 51
1 52
39 53
14 54...

output:

16299011

result:

wrong answer 1st lines differ - expected: '15734930984', found: '16299011'