#D5226. Odd Mineral Resource
Odd Mineral Resource
Odd Mineral Resource
In Homer's country, there are n cities numbered 1 to n and they form a tree. That is, there are (n-1) undirected roads between these n cities and every two cities can reach each other through these roads.
Homer's country is an industrial country, and each of the n cities in it contains some mineral resource. The mineral resource of city i is labeled a_i.
Homer is given the plans of the country in the following q years. The plan of the i-th year is described by four parameters u_i, v_i, l_i and r_i, and he is asked to find any mineral resource c_i such that the following two conditions hold:
- mineral resource c_i appears an odd number of times between city u_i and city v_i; and
- l_i ≤ c_i ≤ r_i.
As the best friend of Homer, he asks you for help. For every plan, find any such mineral resource c_i, or tell him that there doesn't exist one.
Input
The first line contains two integers n (1 ≤ n ≤ 3 ⋅ 10^5) and q (1 ≤ q ≤ 3 ⋅ 10^5), indicating the number of cities and the number of plans.
The second line contains n integers a_1, a_2, ..., a_n (1 ≤ a_i ≤ n).
Then the i-th line of the following (n-1) lines contains two integers x_i and y_i (1 ≤ x_i, y_i ≤ n) with x_i ≠ y_i, indicating that there is a bidirectional road between city x_i and city y_i. It is guaranteed that the given roads form a tree.
Then the i-th line of the following q lines contains four integers u_i, v_i, l_i, r_i (1 ≤ u_i ≤ n, 1 ≤ v_i ≤ n, 1 ≤ l_i ≤ r_i ≤ n), indicating the plan of the i-th year.
Output
Print q lines, the i-th of which contains an integer c_i such that
- c_i = {-1} if there is no such mineral resource that meets the required condition; or
- c_i is the label of the chosen mineral resource of the i-th year. The chosen mineral resource c_i should meet those conditions in the i-th year described above in the problem statement. If there are multiple choices of c_i, you can print any of them.
Example
Input
6 8 3 2 1 3 1 3 1 2 1 3 2 4 2 5 4 6 3 5 1 1 3 5 1 3 3 5 1 3 1 1 2 2 1 1 3 3 1 4 1 5 1 6 1 3 1 6 1 3
Output
-1 2 3 -1 3 2 2 3
Note
In the first three queries, there are four cities between city 3 and city 5, which are city 1, city 2, city 3 and city 5. The mineral resources appear in them are mineral resources 1 (appears in city 3 and city 5), 2 (appears in city 2) and 3 (appears in city 1). It is noted that
- The first query is only to check whether mineral source 1 appears an odd number of times between city 3 and city 5. The answer is no, because mineral source 1 appears twice (an even number of times) between city 3 and city 5.
- The second and the third queries are the same but they can choose different mineral resources. Both mineral resources 2 and 3 are available.
inputFormat
Input
The first line contains two integers n (1 ≤ n ≤ 3 ⋅ 10^5) and q (1 ≤ q ≤ 3 ⋅ 10^5), indicating the number of cities and the number of plans.
The second line contains n integers a_1, a_2, ..., a_n (1 ≤ a_i ≤ n).
Then the i-th line of the following (n-1) lines contains two integers x_i and y_i (1 ≤ x_i, y_i ≤ n) with x_i ≠ y_i, indicating that there is a bidirectional road between city x_i and city y_i. It is guaranteed that the given roads form a tree.
Then the i-th line of the following q lines contains four integers u_i, v_i, l_i, r_i (1 ≤ u_i ≤ n, 1 ≤ v_i ≤ n, 1 ≤ l_i ≤ r_i ≤ n), indicating the plan of the i-th year.
outputFormat
Output
Print q lines, the i-th of which contains an integer c_i such that
- c_i = {-1} if there is no such mineral resource that meets the required condition; or
- c_i is the label of the chosen mineral resource of the i-th year. The chosen mineral resource c_i should meet those conditions in the i-th year described above in the problem statement. If there are multiple choices of c_i, you can print any of them.
Example
Input
6 8 3 2 1 3 1 3 1 2 1 3 2 4 2 5 4 6 3 5 1 1 3 5 1 3 3 5 1 3 1 1 2 2 1 1 3 3 1 4 1 5 1 6 1 3 1 6 1 3
Output
-1 2 3 -1 3 2 2 3
Note
In the first three queries, there are four cities between city 3 and city 5, which are city 1, city 2, city 3 and city 5. The mineral resources appear in them are mineral resources 1 (appears in city 3 and city 5), 2 (appears in city 2) and 3 (appears in city 1). It is noted that
- The first query is only to check whether mineral source 1 appears an odd number of times between city 3 and city 5. The answer is no, because mineral source 1 appears twice (an even number of times) between city 3 and city 5.
- The second and the third queries are the same but they can choose different mineral resources. Both mineral resources 2 and 3 are available.
样例
6 8
3 2 1 3 1 3
1 2
1 3
2 4
2 5
4 6
3 5 1 1
3 5 1 3
3 5 1 3
1 1 2 2
1 1 3 3
1 4 1 5
1 6 1 3
1 6 1 3
-1
2
3
-1
3
2
2
3
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