#P4320. 道路相遇
道路相遇
Output Format
Output lines, each containing a single positive integer.
5 6
1 2
1 3
2 3
3 4
4 5
3 5
1
1 5
3
Hint
From city to city there are possible routes:
It can be seen that Xiao w will always pass through cities , so the answer is .
You may assume Xiao w will not visit the same city twice. Of course, even if you think revisiting cities is allowed, it does not affect the answer.
Subtask 1: 15 points, .
Subtask 2: 15 points, .
Subtask 3: 20 points, .
Subtask 4: 20 points, .
Subtask 5: 30 points, .
Constraints: For all testdata: $1 \leq n \leq 5 \times 10^5, 1 \leq q \leq 5 \times 10^5, 1 \leq m \leq \min(\frac{n(n-1)}{2}, 10^6)$.
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