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Parent and son

Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 65768/65768 K (Java/Others)
Total Submission(s): 2803    Accepted Submission(s): 701


Problem Description
Give you a tree with N vertices and N‐ 1 edges, and then ask you Q queries on “which vertex is Y's son that has the smallest number and which vertex is Y’s descendants that has the smallest number if we choose X as the root of the entire tree?”
 

Input
The first line of input is an integer T (T<=10) means the case number.
The first line of each test case contains N(2 ≤ N ≤ 100,000) and Q(1 ≤ Q ≤ 100,000).
Each of the following N ‐ 1 lines of the test case contains two integers a(1 ≤ a ≤ N) and b(1 ≤ b ≤ N) indicating an edge between a and b.
Each of the following Q lines of the test case contains two integers X(1 ≤ X ≤ N) and Y(1 ≤ Y ≤ N, Y ≠ X) indicating an query.
 

Output
For each query, output the Y's son which has the smallest number and Y's descendant that has the smallest number if X is the root of the entire tree. If Y has no sons then output “no answers!”. There is an empty line after each case.
 

Sample Input
1 7 3 1 2 1 5 2 3 2 4 5 6 5 7 1 2 5 3 3 2
 

Sample Output
3 3 no answers! 1 1
 

Source
 

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